TNT Duplication Bug

This machinery here can duplicate TNT. I am uploading the machine to imgur because for some reason I can't upload here. https://imgur.com/a/PRraI
It uses

• 1 DROPPER
• 3 OBSERVER
• 2 STICKY PISTON
• 8 SLIMEBLOCKS
• 2 RAIL DETECTOR
• 1 MINECART
• 1 COMPARATOR
• 5 REDSTONE REPEATER
• 4 REDSTONE
• 1 TNT
• 1 LEVEL
• 7 BUILDING BLOCKS (Stonebrick)