This happens a lot with pistons. It happens because they are in different chunks. I don't know the reason why they behave this way, maybe different chunks have a different activation order.
This is easily avoidable, however. A chunk will always have the same activation order for all pistons, even if you save and quit. It is quite unfortunate if you need the piston to be in a specific chunk but that's just how it is.
An examples of this happening is a double piston extender using a similar trick to the one you used here. Another is a zero-tick piston extender (piston extender which skips the 1 redstone tick delay that pistons have when retracting) which requires two pistons to work, depending on the chunk the zero-tick piston extender will have different configurations.
This happens a lot with pistons. It happens because they are in different chunks. I don't know the reason why they behave this way, maybe different chunks have a different activation order.
This is easily avoidable, however. A chunk will always have the same activation order for all pistons, even if you save and quit. It is quite unfortunate if you need the piston to be in a specific chunk but that's just how it is.
That can't be the whole story, I can get the same pair of pistons to behave differently depending on on which side I connect the redstone signal.
And it seems to happen when I build them in the center of a chunk.
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And I'm not seeing any difference from one chunk to another so far.
Almost all pairs are having the bottom piston extend, in all chunks and most places in the chunk but close to the middle I'll get the top piston extending when I power them from one direction and the bottom extending when powered from the other three directions.
Still not finding any difference from chunk to chunk.
What I'm seeing so far is a checkerboard pattern where piston pairs on the red squares extend the upper piston when powered from the north, piston pairs on the purple squares extend the upper piston when powered from the south and piston pairs on the bedrock squares always extend the bottom piston.
Can someone tell me why this happened?
Is this bug?
Version:1.16.5
All I know is that if the upper piston extends first it will block the lower.
But I don't seem to be able to get that to happen, whichever direction I build this in I get it looking like your right one.
Is it the same every time or does it vary?
Just testing.
It's the same every time but I think it cound be right one before.
This happens a lot with pistons. It happens because they are in different chunks. I don't know the reason why they behave this way, maybe different chunks have a different activation order.
This is easily avoidable, however. A chunk will always have the same activation order for all pistons, even if you save and quit. It is quite unfortunate if you need the piston to be in a specific chunk but that's just how it is.
An examples of this happening is a double piston extender using a similar trick to the one you used here. Another is a zero-tick piston extender (piston extender which skips the 1 redstone tick delay that pistons have when retracting) which requires two pistons to work, depending on the chunk the zero-tick piston extender will have different configurations.
That can't be the whole story, I can get the same pair of pistons to behave differently depending on on which side I connect the redstone signal.
And it seems to happen when I build them in the center of a chunk.
--
And I'm not seeing any difference from one chunk to another so far.
Almost all pairs are having the bottom piston extend, in all chunks and most places in the chunk but close to the middle I'll get the top piston extending when I power them from one direction and the bottom extending when powered from the other three directions.
Just testing.
Still not finding any difference from chunk to chunk.
What I'm seeing so far is a checkerboard pattern where piston pairs on the red squares extend the upper piston when powered from the north, piston pairs on the purple squares extend the upper piston when powered from the south and piston pairs on the bedrock squares always extend the bottom piston.
(The screenshot was taken facing north.)
--
This doesn't seem to be quite right either.
Though it still seems mostly right.
Just testing.