YI ZHUANG

Confirmed in 1.15.2.

But the first dispenser can work if input continuous high frequency pulse (like pull the lever very quick for some time), not knowing why.

I think the same issue happens in 1.15.2 too. Is it fixed in 1.16 snapshots but reappeared in 20w19a?

This problem still exists in recent version (I tested in 1.8, 1.14, 1.15.2 and 20w18a), and I find if the redstone dust above the solid block above the piston, has power level 2 or 4 or 6 or 8, then this problem would arise. Under other power level the piston would not enter BUD state.

The setting to see this problem is a little critical. The piston should be placed under a solid block, not beside(at same height). piston should not be placed against another piston that is controled by the same circuit. Transparent block like glass also prevent piston entering BUD state.

It also works for dispenser, dropper.