There are 3 bugs I found. First you have the candle duplication. Put a candle on a cake and then go in survival mode. Right click the cake to eat it and it will dupe the candle. 

Secondly, put a ametyst cluster on a stickypistons face. Give the piston power so it extends. When it retracts it will drops ametyst crystals.  With a 4 tick clock you can automise.

Shulker boxes will open like a shulker if there is a loaded shulker.