[michaelbenson]

Originally Posted by xlguy

We've had users clear their cookies, and check their privacy settings are default to Medium and we're still getting random logouts on 3.5.3. The plugins we have are:

• Archive Adsense 1.0
  Edit New Thread Button 1.1
  Extended Signature Limits 1.0.3
  Form Hack 3.3
  HELLCATs Realtime Page Compressor 1.24
  Moderator Stats 1.2
  Reported post creates new thread 2.01
  Security Fix for Issue in vBulletin 3.5.3
  SigmaChat 1.0.0 SigmaChat integration
  Strike Through Closed Threads 1.0.0

I can't see how any of these would affect it. Such a strange issue this, there are plenty of people reporting it across vB.com and .org but at the same time plenty of people without the problem. I wonder what the common link is?

Perhaps it would be best to actually upgrade to the later versions and not just apply security fixes/patches? I havent personally encountered this error and i seem to be using some similar modifications to you too.