https://bugzilla.kernel.org/show_bug.cgi?id=207383
--- Comment #57 from Anthony Ruhier (anthony.ruhier@gmail.com) --- To give some precision about the kernel version range, I'm staying on 5.6.19 for a while, which doesn't have the issue. It's pretty bad though, as it's EOL.
Only the 5.7 branch has it. So it's something that wasn't backported.
I also have multimonitors, with one with VRR, though I don't know if VRR changes anything in my case as the 2 other screens don't support it.