I am using a laptop and 2 monitors connected to it (laptop display is set as main). While using those monitors, in some situations (didn't observe a cause to trigger this effect), when an application is maximized and focused on secondary display - it's interface is duplicated on the main display like in the gif below:
As you can see, when I focus on the app on the monitor it is duplicated on the laptop display, which isn't a normal behavior.
Ubuntu 22.10, kernel version 5.19.0-26-generic
This is my xrandr output in case it might help:
XWAYLAND0 connected 1920x1080+0+120 (normal left inverted right x axis y axis) 530mm x 300mm
1920x1080 59.96*+
1440x1080 59.99
1400x1050 59.98
1280x1024 59.89
1280x960 59.94
1152x864 59.96
1024x768 59.92
800x600 59.86
640x480 59.38
320x240 59.52
1680x1050 59.95
1440x900 59.89
1280x800 59.81
720x480 59.71
640x400 59.95
320x200 58.96
1600x900 59.95
1368x768 59.88
1280x720 59.86
1024x576 59.90
864x486 59.92
720x400 59.55
640x350 59.77
XWAYLAND2 connected primary 1920x1080+1920+120 (normal left inverted right x axis y axis) 340mm x 190mm
1920x1080 60.05*+
1440x1080 59.99
1400x1050 59.98
1280x1024 59.89
1280x960 59.94
1152x864 59.96
1024x768 59.92
800x600 59.86
640x480 59.38
320x240 59.52
1680x1050 59.95
1440x900 60.03
1280x800 59.99
720x480 59.71
640x400 59.95
320x200 58.96
1600x900 59.95
1368x768 59.88
1280x720 59.86
1024x576 59.90
864x486 59.92
720x400 59.55
640x350 59.77
XWAYLAND3 connected 1920x1200+3840+0 (normal left inverted right x axis y axis) 520mm x 320mm
1920x1200 59.88*+
1600x1200 59.87
1440x1080 59.87
1400x1050 59.86
1280x1024 59.76
1280x960 59.94
1152x864 59.78
1024x768 59.68
800x600 59.86
640x480 59.38
320x240 59.52
1680x1050 59.85
1440x900 59.89
1280x800 59.81
720x480 59.71
640x400 59.20
320x200 58.96
1920x1080 59.88
1600x900 59.82
1368x768 59.88
1280x720 59.86
1024x576 59.90
864x486 59.45
720x400 59.55
640x350 59.77
