I've serious glitches (and the game is unplayable), only if there is more than 8 players.
I tried reinstalling the game with Steam, updating my graphic card drivers,... nothing helps.
I played 2 sessions (one with 8 players and one with 12) in debug mode, hoping there is something relevant.
Another thing, the CPU core running the FAF client is at 100% before the game starts (but it calm down after game begin).
I have a Ryzen 9 3900X, RX580 GC and 16 GB Ram.