I managed to find a solution with help from this reddit post, but the workaround for this bug didn't work out of the box and so I'll post an answer here too.
First of all, the effect is caused by the "sticky window snapping" kwin script. Not usually a problem but apparently a bug prevents users from accessing its configuration gui to remove this effect. So to get the settings back type:
The first command creates a folder called kservices5 into which the second command then copies a file. Now press Alt+F2 and run kwin --replace.
Then open the settings app (close it if it was previously already open) and go to the kwin scripts section and tweak the sticky window snapping settings to match your preferences.
I managed to find a solution with help from this reddit post, but the workaround for this bug didn't work out of the box and so I'll post an answer here too.
First of all, the effect is caused by the "sticky window snapping" kwin script. Not usually a problem but apparently a bug prevents users from accessing its configuration gui to remove this effect. So to get the settings back type:
The first command creates a folder called kservices5 into which the second command then copies a file. Now press Alt+F2 and run
kwin --replace.Then open the settings app (close it if it was previously already open) and go to the kwin scripts section and tweak the sticky window snapping settings to match your preferences.