Los pistones no funcionan correctamente como antes
Al poner un bloque de Redstone en una esquina de un pistón, éste se activa por alguna razón... Y todavía peor, si lo quitas el pistón seguirá activado aún así.
Ésto puede afectar mucho en construcciones de Redstone que ocupen bloques de slime o bloques de Redstone.
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Thank you for your report!
We're actually already tracking this issue in MC-108, so I resolved and linked this ticket as a duplicate.
However, that ticket has already been resolved. Depending on the resolution, that can mean that it either will be fixed in the next version, or that it is not considered a bug and won't be fixed.
If you haven't already, you might like to make use of the search feature in the future to see if the issue has already been reported.