when both the mechanical bearing or mechanical piston is activated it results in a crash. trying to load the map afterward will still cause it to crash. the only way I've found to fix this is to erase the block using editing software like mcedit or amulet. crash log for both piston and bearing:
crash-2022-01-09_15.19.03-client (bearing).txt

crash-2022-01-09_15.45.21-client (piston).txt

Thanks for the report! This crash has been fixed in the latest version (update Flywheel, too).