Ryan H.

I'll include it in the next update. I don't intend to release a new version for one file for something that isn't broken except for when you try to run the support diagnostic. If it bothers you, the file as Gabriel/IPS so helpfully provided will fix it.

This has been already pointed out to the developer: 
See the posts after this one for the developer's answer and a possible solution.

I'll include it in the next update. I don't intend to release a new version for one file for something that isn't broken except for when you try to run the support diagnostic. If it bothers you, the file as Gabriel/IPS so helpfully provided will fix it.

Getting a bit off-topic, but I appreciate the perspective.
In general, I would always advocate running a development/test copy of production, where you try any upgrades and changes before doing it live. That should help catch issues before they become much bigger issues. Routine backups are a good idea regardless. That being said:
I feel your pain. Lack of backwards-compatibility is definitely a big issue (my other app was plagued by it for a while, in one case they tweaked a feature three different ways in three consecutive releases), and contributor rants on the subject are long and numerous. There's not much to be done about it. IPS insists on being able to refactor and fix framework bugs as deemed necessary, at any time. To their credit, they have made an effort to try maintaining BC, post about breaking changes in advance, and make pre-release builds available. That's an improvement over what it was. Still, always unintended side-effects (see: this).
I understand their perspective, and they do what they have to do for their own business interests. Telling people, 'hey, we won't be able to fix this bug until the next major release in a year or two because it might break other stuff' isn't an option as far as they're concerned.
The flip side, of course, is that they've created an ecosystem with little semblance of stability. It's cumbersome to maintain anything substantial on it, and I think the number and state of contributors around is demonstrative.
It may be there are different design decisions they could've made to alleviate these issues--a more rigid and compact core, or a formal API and semantic versioning, or TDD, or using a common framework like Symfony... but that's largely immaterial. Not the reality we live in.
As for me, I try to fix my stuff when it breaks, but I've moved on to other pastures.

The 4.1.14 update was one of the most disruptive updates to my site in the last year or two. Immediately after updating I got tons of complains about members not being able to login and other issues. 
I have been running Easy Pages for quite a long time. I also experienced some of the same issues noted above. It didn't stop with the Easy Pages app either. There were many other problems - all of which worked fine before 4.1.14.
At first, I was able to partially work around the new login url problem  by doing some server based rewrites / redirects.
Ultimately, more problems surfaced and I gave up and converted what Easy Pages I had to the regular Pages app. It seems over time, the Pages app has added much of the Easy Pages functionality to it anyway.
This was still hard because many of the features I used it for I had to change or get rid of completely during the migration.
After this, I had to uninstall Easy Pages. Then I also had to reset my Furls to defaults. Then recached the site. 
This fixed most of the problems. User logins were now working properly rather than retuning error pages. 
However there were still problems unrelated to Easy Pages. It seems after resetting Furls to defaults, there were a few native IPS calls still using the old format that were not reflected in the new default Furls. So I had to go into the source code and work around those. 
And second to last of my problems, a number of url formats I used for custom theme changes previously were now broken - such as calling a topic with just a dash after it and nothing else now required two dashes. 
And the last present of 4.1.14 was some type of IPS search index task update that caused my sql server to nearly lock up so bad it caused my website to timeout while it was running. After a few days, I was able to isolate this as the problem and just set my site to only index 3 days of data so it would calm down this problem. There is a thread about this problem elsewhere on the forum.
So what went from a seemingly routine IPS incremental update, turned out to be the nightmare of the year for me. All told it probably took me a week to sort out the mess.
I will certainly take all updates very seriously from now on with full backups done immediately before so I can immediate roll back and research when this type of thing happens again. I will also likely skip many of the updates since they can cause so many problems.
As it is, it has become more common to find an increasing number of plugins and updates and template changes and urls breaking on each IPS update. I can see why the cost to develop modifications for IPS 4 has gone up. Their shelf life may be only as long as a few weeks until the next update. At the same time, the number of modifications and functionality / performance of the forum software itself are a mere fraction of what used to be available in the IPB 3 days.
For crying out loud, to this day I still have to rely on using a Google search for indexing my forum rather than the built in high performance Sphinx searching of days gone by.

A solution is not going to come easily. Unless IPS changes something, I don't see any real option except changing all page URLs.
I opened a bug report. We'll see what happens.
 

I can reproduce the problem reliably now, on my own install. Definitely a 4.1.14 compatibility problem. Any root URL with a query string seems to do it -- login post-redirect happens to create such a URL.
Still working on how to resolve this.

'Has anything changed in fURL handling recently, that might explain why this was never a problem prior to now?'

Already explained above how to solve this: 
 

Are you trying to remove an actual prefix, or "[beta] ..." text at the beginning of topic titles? That tool removes text from topic titles. If you want to remove an actual prefix, look at the tag manager.

Thank you.

You should copy-and-paste any information from ACP > Support > Error Logs or System Logs which can help him diagnose much faster.  

I work a full-time job. I have other responsibilities. I am not ignoring you, I just have not had time to investigate yet following your PM. Please be patient.

Got it. Yes, that should work as expected.
 
Understood, thanks. I'll look into it for the next update, but otherwise, unless you see something break, you can disregard the "DB errors" the support tool reports. The support tool is known (notorious) for misinterpreting the database schema, writing it one way and then reading it as something different, when it's actually the same. Evidently they changed something about it in 4.1.14, and this was a side effect.

Got it. Yes, that should work as expected.
 
Understood, thanks. I'll look into it for the next update, but otherwise, unless you see something break, you can disregard the "DB errors" the support tool reports. The support tool is known (notorious) for misinterpreting the database schema, writing it one way and then reading it as something different, when it's actually the same. Evidently they changed something about it in 4.1.14, and this was a side effect.

Thanks. If the CSSdisplay modes allow it...yeah, that would be an easy fix. I can do roughly the same change from the app. Will see about that for next update.

Ach. Must be a side-effect of the text wrapping issue I fixed. I'll have to see if there's an alternate class/approach I can use to fix that, or something I can coopt to add a little margin back in. I'm trying really hard to avoid any actual custom styles.

Ach. Must be a side-effect of the text wrapping issue I fixed. I'll have to see if there's an alternate class/approach I can use to fix that, or something I can coopt to add a little margin back in. I'm trying really hard to avoid any actual custom styles.

Ach. Must be a side-effect of the text wrapping issue I fixed. I'll have to see if there's an alternate class/approach I can use to fix that, or something I can coopt to add a little margin back in. I'm trying really hard to avoid any actual custom styles.

I'm aware, actually looking into it right now. Still trying to figure out what they actually changed on me to cause this.
e: found it. They added a bunch of ipsContained classes and table layout styles that are screwing up the work breaks.

There was when you bought it. Removed it a while later, that change isn't retroactive though. I generated a new purchase for you.

I've published an update to resolve all of the compatibility problems I'm aware of. If you have a problem, please update. If that doesn't fix it, explain what's going on.
I do not have Pages, and I have not gotten any confirmation of whether the Pages conflict is still occurring, so that issue may still be out there. If so, I'll need access to someone's site to investigate. Last I hear, though, it may be a non-issue now.
What's New in Version 3.1.7
Fixed tag overriding prefix when the same value is added as both. Fixed style changes in IPS 4.1.13 breaking multi-word prefixes. Fixed template changes in IPS 4.1.13 breaking display of prefixes on site index. Fixed potential errors with applying prefixes from saved actions. Fixed tag/prefix changes from saved actions not updating the search index (profile, activity stream, search results). Fixed possible division-by-zero error on the tag cloud widget. Added prefix to core topic widgets. A few issues I could not reproduce:
Prefix not showing on grid view (works for me) Prefix input not displaying when creating a topic, with forum in prefix-only mode. (works for me) Homepage topic feed widget -> topic titles not linking when a prefix is present. (This must have been something custom; AT&P didn't add any such thing until, well now.) Fair warning: Most of the app will probably still work back to 4.0.0, but I will not guarantee backwards compatibility across the board anymore. It's just not worth the trouble with how frequently (and massively) things change from one release to the next. If you're running an old IPB version and you have an issue with an AT&P update, I'm going to tell you to update.

I'm aware, actually looking into it right now. Still trying to figure out what they actually changed on me to cause this.
e: found it. They added a bunch of ipsContained classes and table layout styles that are screwing up the work breaks.

Done.