The last 2 days the forum isn't displaying right, the banner and sidebar are underneath the list, if at all, so is the inbox and all the account stuff. I was clicking around and every other time it would be screwed up. Now it's not right at all. Tried clearing cache, switching browsers, a friend verified that it also looked weird to her. I'll add some screen shots...
More and more sites are starting to complain of this - and invariably it's on the refresh and with an error 500 on the css. Wonder what is in common (older version of PHP?, running mod_security?, Apache 2 vs nginx?, shared host, VPS, dedicated server?). Is there a commonality in the hosting providers?
I do know that on my site (running latest official build) I can hit refresh as many times as I want, as fast as I want and never have the problem. May have something to do with the fact that I'm running on a dedicated server that I set up and not a shared hosting site that is dependent on the hosting company to configure.
I'm having the same exact problem on my site as well, I only discovered it today. As pointed out, it only happens when you refresh the page. If you click links, everything is fine.
I don't know how long ago this problem started, so I don't know if it is related to upgrading Xenforo versions. I do know that I did not have this refresh problem prior to the upgrade.
Good thing I ran into this thread, I was about to do a clean reinstall. (Hopefully a solution would be found so it can be avoided)
Hosted on fatcow.com
Not sure about mod_security, I suppose I would have to shoot an email to my webhost.
I don't know what I'm running, hosted with ipage. I know that this was not an issue before 1.1.5 because we make use of that refresh button during chat times to see who's registering and coming in because they kinda just sit there unless you engage them.