I found a bug if you make a wall with a piston and a button above the piston and redstone behind the button. If you press the button the piston will stay extended. If you do like break a block that is touching the piston it will extract. If you can fix this I would be happy. I made a video on this but didn't post it. Here's a link to the video:
https://www.mediafire.com/?rk1ztbmc4ben445
Related issues
Comments

Thank you for your report!
However, this issue has been resolved as a Duplicate of MC-108.
It has been linked to this report. If you have additional information, please add it to that report.
Please search before reporting, as it's likely that one exists already.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 Game Wiki