Piston Crash Bug (Reproducible)

It can delete anything (bedrock included) and in some cases transmute pistons into various stone types

Also, it can change one or multiple pistons/sticky to stone:

Affects 1.2.8. If you look at the attached sample, the crash only happens for me when the double piston on the right is fully extended and tries to be pushed by by the pistons on the left while they’re retracting. Only the photo beginning with A2EE breaks in my testing.

Also, in some other testing I thought iron bars being the object pushed had something to do with it, but that’s not the case. However, iron bars are the only object that has caused transmutation for me. Pistons on the right just disappeared (no drops) a couple of times, though rare. Crashing is far more common.

I forgot to mention that if you reduce the redstone wiring on the left, thus creating a longer decay in the comparator loop, even A2EE works without breaking. It seems to be something about a piston in a changing state being pushed by a piston with too quick of an actuating pulse.

Here is a simpler test setup. Now, if you decrease the repeater on the left OR completely remove the 2 repeaters on the right it should crash every time. With the setup pictured it BARELY works and seems to be affected by the unreliable repeater bug. So this setup is right on the edge of functionality. (Oddly enough 2 tick repeater on the first setup seems to always deliver 2 ticks to the comparator circuit. I don’t know, but that’s for a different bug report.)

Also, as seen in the picture, one of my tests resulted in transmutation while all the others simply crashed.

Does this count? (I was sent here by a mod)

For those who can't load it. It's a crazy slime block contraption where a sticky piston facing perpendicular to the direction of movement and an observer powering it are moved side to side by two regular pistons powered by redstone blocks on top of the contraption. There are two quartz blocks lined up side by side so the sticky piston should always have something in front of it. I remove the redstone block that is stopping the machine. Here's what the piston does on each stroke of the machine.

Stroke 1 (back stroke): nothing.
Stroke 2 (forward stroke): piston extends and stays put.
Stroke 2.5: piston retracts.
Stroke 3: nothing.
Stroke 3.5: piston extends.
Stroke 4: piston remains extended and stays put, then begins to retract.
Stroke 4.5: piston continues retracting.
Stroke 5: nothing.
Stroke 5.5: piston extends.
Stroke 6: piston remains extended and stays put.
Stroke 6.5: piston retracts.
Stroke 7: nothing.
Stroke 7.5: piston extends.
Stroke 8: piston partially retracts, leaves first block in place, and moves with the machine, it's arm clipping into the second quartz block. It then extends again.
Stroke 8.5: the piston seems extended with it's arm completely inside the quartz block in front of it.
Stroke 9: both the piston and the quartz block move with the machine. The behavior of the piston head is unclear but it seems extended.
Stroke 9.5: the piston drops as an item.

Picture of the initial setup of the machine:

A very painful bug have lost 2 worlds to it now and have noticed that the piston can turn into 3 things that i have seen so far 1. Being stone 2. Polished andcite 3. Andcite

It seems to always happen on the rectraction for fast fireing pistons.

Still affects 1.2.20.1

This is what I made on 1.2.20.1 clicked the button game will crashe but if theres no water on top it should not crash the game. It is auto refiller cauldron