Update: no flickering in this time period.
Downgrading to an older kernel version (5.0.0-050000-generic) solved the problem. Aparently the kernel version 5.8.0-50-generic has some problem between Intel Graphics and Xorg.
Update: no flickering in this time period.
Downgrading to an older kernel version (5.0.0- 050000- generic) solved the problem.
Aparently the kernel version 5.8.0-50-generic has some problem between Intel Graphics and Xorg.