Just in case it might help someone, I've found information that reballing DFU64H1 chip on the t-con might solve the issue.

The other option is replacing t-con entirely.

So it seems at the moment the only known steps are:

1. Reinstalling firmware.
2. Reballing DFU64H1 chip on the t-con.
3. Replacing t-con entirely.

Hello, I have similar issue with a different model [B]Q27G2U/BK[/B].

I'm at my wits end here and the search does not provide any valuable info about how this issue can be nipped in the bud.

Only changing refresh rates back and forth multiple times helped bring the picture back but now any full-screen application causes the monitor to turn black, and switching refresh rates causes the same issue.

My only idea is that something is wrong with the Adaptive Sync implementation on the monitor or the T-CON board.

I think firmware reset could help in...