A stool that is a part of a Spinning wheel looks distorted when a char is not sitting on it. Distortion happens during animation of the stool hovering back under the Wheel.
It is more or less square with a char on it,
and immediately after the weight has been lifted.
Then it hovers under, becoming more like a rhomb.
Probably related to the viewtopic.php?f=47&t=42690 .