Thank you for disabling CloudFlare.
Unfortunately, items 2, 7, and 9 are ones which I can reproduce.
For 7 & 9, as you're using NGINX with custom rewrite rules, I would suggest disabling these to see if this is creating any issues here or switch to using Apache. Unfortunately, NGINX is outside our scope of support.
For 2, it looks like PHP session handle is creating an issue here so this is a server issue rather than a software issue.