UPDATE: On February, the sound and AI are now fixed with a new patch.
On January 31st, a new patch has been deployed. This was an emergency patch to fix a security issue in the game.
Sadly, this patch doesn't fix the AI bug yet, and it reintroduced the 7.1 sound issue. This is something that was acknowledged and planned as such to allow a quick fix of the security issues.
In the meantime, feel free to try out this community fix by Kaldaien while we work on an official patch. (Try this unofficial patch at your own risk, we cannot be held responsible for any issues it may cause).
The team is working to get the sound fixed again ASAP and the AI bug as well.
Vjoy also seems to be linked with crashes, this is being investigated.
Thank you for your comprehension.