I am affected by this bug as well.
My workaroud for this Problem: Go to KDE System Settings -> Display and Monitor -> Compositor (left side) -> set "Rendering Backend" to XRender
But now my wobbly windows are gone ;(
I just upgraded to kubuntu 17.04 and this problem appeared (yeah, I knew an update would take some time, so I waited until I had some spare time).
I am affected by this bug as well.
My workaroud for this Problem: Go to KDE System Settings -> Display and Monitor -> Compositor (left side) -> set "Rendering Backend" to XRender
But now my wobbly windows are gone ;(
I just upgraded to kubuntu 17.04 and this problem appeared (yeah, I knew an update would take some time, so I waited until I had some spare time).