XF 1.5 Clicking New Posts shows another user

[Blackbeard]

When a user is clicking New Post it is showing them logged in as another user. When they click on another page they are put back into their account.

I'm not able to recreate this for me. However 3-6 folks from a number of other sites are reporting the same issue, and I'm not sure where to start looking for this.

 

[Paul B]

Do you have any caching implemented or a reverse proxy?

Which site is it that it's happening on?
I can take a look at the headers to see if there's anything unusual/obvious.

 

[Blackbeard]

www.glocktalk.com
www.ohiogamefishing.com
www.thefirearmsforum.com

we do have a caching system running, memcache.

 

[Paul B]

Try removing the cache to see if that resolves it.

Other than that, the only other thing I can think it could be is an add-on.