Not sure if this is just me, but I have noticed that I cannot log out of my admin/Webmaster profile on my mobile device ever since I completed the update yesterday. 

Is this a known issue being investigated, or an isolated incident?

I think it might be a safari browser issue, as I could log in and out via chrome. 

I can't reproduce this on my test community with safari on ipad. Are you using the default theme?

I am, yes. Default theme is in use, with some minor cosmetic changes (colours etc).