Descriptive Problem Summary:
I've begun to encounter some weird freezes occuring after 30-90 minutes of gameplay.
The screen is still and becomes black when player reconnects.
The only procs working are those called directly by players through verbs or HUD interaction.

I've tried to reproduce the problem by overloading a clean project server with an expensive proc.
It resulted in a heavy lag and player-induced procs didn't work during the test.

Then i set this proc to background and everything was broken as decribed above. But there was a difference - Dream Daemon was frozen as well and I didn't have access to it. And in this case, I could see this costly proc in profiler.

There are several background procs in my project and I've tried to disable them one by one to trace the bug, but it didn't work.
The issue occurs only in the latest version of the project. The rollback is possible, but nevertheless undesirable.

Numbered Steps to Reproduce Problem:
I haven't managed to find any dependence between game events and the freeze.

Does the problem occur:
Every time? Or how often? Every time after 30-90 minutes of gameplay.
In other games? I've found a similar problem described at B12 forums: http://baystation12.net/forums/viewtopic.php?f=5&t=9073
In other user accounts? Yes.
On other computers? Yes.

When does the problem NOT occur? At earlier versions of my project. The updates were large, so I can't figure out which part of the code causes the problem. I will continue debugging process, but I definetly need some advice on what to look for.