Steps to Reproduce:
Build a rail track with a powered powered rail going straight into a block (see video).
Place the TNT Minecart on one end and modify it to set its
explosion_power
nbt tag to0.0f
.data modify entity @n[type=tnt_minecart] explosion_power set value 0.0f{\code}
Push the TNT Minecart into the side of the block using the track, causing it to explode.
Observed Result:
The powered rail the TNT Minecart was on breaks, and sometimes the block below it will break too. Due to the randomness of explosions, you may need to repeat this a few times to get this result.
Expected Result:
No blocks are broken as the explosion power is zero.
Can confirm:
[media]