No idea why but Fabrication v1.3.3 on Fabric 1.16.5, changing your size and then opening your inventory to a window where the avatar/player renders will reset your size but only client-side, so jumping and moving bugs out and may randomly kill you.

This only happens if Omniscient Player Config is turned on

turned off in the screenshot of course

it entirely breaks the mod please fix :)

Fixed on Fabrication's end. Once they release a new version this should work properly.