Piston Duplication using TNT and Redstone

Steps to Reproduce:

1. Download and open the attached world (note that the world can only be opened in 1.16.210.53 Beta or a higher version)
2. Press the oak button
3. If the pistons do not duplicate, replace the destroyed redstone dust underneath and replace the TNT
4. Press the oak button again
5. Repeat steps 3-4 until the pistons duplicate

Observed Results:
Piston items sometimes drop despite no pistons being broken.

Expected Results:
No piston item should drop.

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Original Description:
I found an easy to do Piston Dupe using TNT and Redstone. Here is a video of the following and it's setup.