1. Place piston w observer pointing into it
2. Trigger observer repeatedly

Compare in vanilla and with quark.

In quark, block 36/moving_piston basically doesn't render at all, meaning there's no animation of the piston head and moved block at all, it just flickers between unextended and extended which is very ugly/jarring.

(NB: You may run into a separate bug while testing this where translucent blocks don't render when being moved in fabulous mode, that's a forge bug, not quark.)