Yes... I am SURE.
Installing kb5003214, groupy active, reboot, task bar broken (see images above).
removing kb5003214 groupy active, task bar working again.
installing kb5003214 + groupy active, broken again.
deactivate groupy + reboot with kb5003214, working.
enabling groupy + reboot with kb5003214, broken.
deactivate groupy + reboot with kb5003214, working again.
I dont use ANY other programs which alter Windows 10 21h1 19043.1023. It is a german system, 4k resolution, 200% dpi scale.