[Sylanael]

Yes, I have noticed that You have polish first and last name, so we can switch to polish if its ok for You

Yes, I am using 3 monitors at the same time, rest of monitors works currently:

Standard monitor(horizontal position): DELL U2412M
2x Standard monitor(pivot position): DELL P2217

U2412M works currently on DP
2x P2217 HDMI and DP

When I disconnect one monitor so have setup:

U2412M DP 1x P2217 DP - Display is lagging, you can notice that when resizing window(full screen and coming back to partial screen)

U2412M DP 1x P2217 HDMI - Display is lagging, you can notice that when resizing window(full screen and coming back to partial screen) - no difference

U2412M DP 2x P2217 HDMI and DP - Display on P2217 on HDMI is working as expected, another P2217 on DP is having issues

1) No issues on Mac display in any case
2) Sometimes during higher load, those lags are more noticeable and mouse cursor starts to lag as presented on video above
3) It seems also that mouse lags are somehow correlated with some interactivity of website? When website has sth like that mouse starts lagging
4) Also checked the setup on windows and haven't seen similar issues, maybe sometimes like in point 3, but in general browser resizing works correctly

I also have recorded some films and sent you link on email and private msgs so you can understand problem better I believe

Kind Regards,
Sylanael