Happens reliably on rotating farms, however mostly seems to happen while the server is empty. The entire system and everything within 50 blocks of it is force-loaded though.

Contraptions keep spinning properly, but harvesters start to ignore all crop blocks, including second layer of sugar cane and similar. Stopping and restarting rotation without placing the blocks back in the world doesn't help. Placing the block and reforming the contraption does, but that removes the crops at the stopping point, so also not ideal.

Only seems to happen on bearings, minecart and piston contraptions work fine.

This issue has been addressed in 0.2.3. Thanks for the report and feel free to re-open if need be.