[BUG] Connection issues in player rooms

[AppelJoosh]

Sometimes when I try to play I either manage to get matches to only last three rematches, or I am unable to get the match to start in the first place. We can get to character select consistently, but loading into the actual match is where the issues start occurring. Once in the match there are usually no issues.

I've had this problem twice with a time difference of 3 months between each occurrence, and I haven't been able to consistently figure out what triggers the bug. I tried disconnecting my Panthera to use my keyboard by itself instead, which didn't fix anything, I've tried turning off Steam Input, I've tried verifying game cache and gotten no missing/corrupted files. What did fix it when this happened three months ago was downloading DDU and using it to clean out any leftover NVIDIA graphics drivers from updates, and then reinstalled the newest one, but three months later the problem has reared its ugly head again.

I could use DDU to do a deep clean again, but this is such a time-consuming solution to the problem that I'd rather not have to do it twice in less than half a year. This problem does not occur in Melty Blood: Type Lumina or Under Night In-Birth 2, which leads me to believe the issue is specific to Centralfiction. I've yet to check Cross Tag Battle, Guilty Gear Strive or Rev2, but I would not be surprised if the issue wasn't present in any of those games.

Any ideas on how to fix this?

EDIT:
Additional details; when hosting and the connection fails, I get the error "Connection was lost" while the other person gets "Room was disbanded". If I join someone else's room I also get "Room was disbanded".