Unity 5.4.0 Regular Crash

It have been confirmed in my project that Unity 5.4.0b15 and 5.4.0b17 have regression compared to Unity 5.3.3f1 which causes crashes freezing whole player.

Symptoms:
- No error is logged
- Player freezes usually when using extensively new Unity UI
- When player freezes it becames covered by white layer or stops and then shows system message "application stopped responding"

hardware we have spotted this on:
- Operating systems which issue was spotted (Test was only on Windows Machines):
Windows 10, 8.1, 8, 7 and 7 SP1
All 32 and 64 bit systems excluding windows 8 and 8.1 which I have registered issue only on 64 bit machines. It mightbe due to the fact that players does not have 32 bit windows 8.

DX versions:
- DX Version: Direct3D 11.0 [level 10.1]
- DX Version: Direct3D 11.0 [level 11.0]

Issue have not been spotted on machines with DX9 althought I'm not sure if this is indeed related or just luck.

- VRAM range 0.7GB - 2GB
- Both ATI and Nvidia GPUs


Main issue:
This issue shows only on some machines, but it does show regularly there (eg every 15-30 minutes). We do not own any of the machine which shows the symptoms but about 5% out of ~500 players playing daily does get this issue.

Solution:
Dont use multithreaded rendering: -force-gfx-direct

I might not be often on this forum so if any further questions show up, especially from Unity team, please contact me via khash/at/muhagames.com

Cheers!