X screen stops refreshing after VT switch
I have currently updated to openSUSE Leap 15.1, X Server version 1.20.3. Now after X start, then screen stops refreshing after a short while. The mouse cursor is still visible and refreshed but any updates to windows or newly open windows are not visible. One reliable way how to trigger is to switch to VT and then back to X. Also when the screen stops refreshing and I switch to VT and back to X, the screen is properly updated to current state but still frozen. Switching to VT is not the only way to trigger this. Another reliable way seems to be to try opening xfce 'Applications' menu. I've tried also IceWM but it has the same problem.
I've found https://bugs.freedesktop.org/show_bug.cgi?id=110808 which seems to be same issue but the guy got redirected here and I couldn't find the bug description in this bugzilla.
X.org.log is attached. I've noticed somewhat strange lines there like:
[ 11.050] (II) AMDGPU(0): EDID vendor "BOE", prod id 1671 [ 11.050] (II) AMDGPU(0): Printing DDC gathered Modelines: [ 11.050] (II) AMDGPU(0): Modeline "1920x1080"x0.0 152.60 1920 1968 2000 21
which repeat several times and then every time after switching from VT to X. Maybe it's related to the problems.