Waterlogged leaf cobblestone farm

A large cobblestone generator for survival worlds. Lava and water held in waterlogged leaves form columns of cobblestone, and a TNT duper at the top keeps dropping TNT that blasts them apart. Water streams carry the drops past a stonecutter into hoppers and chests. It suits anyone who needs building stone in bulk, and the description puts the build at about an hour. Storage fills fast, so plan for extra chests or a shulker box loader.

• If the TNT does not dupe, turn on piston duplication on the server (allow-piston-duplication on Paper, off by default on Paper and Aternos) and remove the Alternate Current mod. Over a dozen comments report it.
• If one side of the cobblestone does not blow up, remove any extra redstone dust behind the dropper. Comment with 96 likes, others confirm.
• Switch the farm off before you leave or log out. When its chunks unload while it runs, the TNT blows up the farm. Comment with 30 likes, many builders report it.
• A repeater set to 3 ticks at 13:46 shows 1 tick after the cut at 14:23, five comments point it out. A comment with 10 likes says keep the first repeater on 1 tick, or two columns stay unbroken.
• If one or two columns stop breaking, switch the farm off and on again, one builder cleared the stuck cobblestone first. Four builders report it fixed theirs.
• Build the glass walls of the collection a few blocks higher, or blasted cobblestone lands outside the water. Three builders report it.