Watch this video for a video tutorial :
https://youtu.be/kd6dOAJA9Vc
Short summary of issue:
-Piston with pushable Redstone block (upwards) will stay permanently extended once the piston got activated via a button or any other temporary redstone signal
Dear Mojang Team, Im thankful for all the support, updates and changes you make to minecraft. Please consider fixing these issues, as they do NOT work as intended.
Dear Moderator that will assign an Admin/Dev to this thead, please do not assign this issue to
ProfMobius if he is still active.I have made earlier posts but never got any reply to my threads. Thank you.
Yet I have not found this glitch reported.
Related issues
Comments

This is due to quasi-connectivity: Pistons can be powered by blocks 2 blocks above them, such as the redstone block it's pushing. This used to be unintended, but the redstone community used it for so many things that Mojang kept it to keep redstone machines working. While this is unintended, it will not be fixed because it will break many other things.