If you put two sticky pistons right on top one another facing up and power just the bottom piston the top piston will stay attached to the bottom piston. But if you power both the bottom piston and top piston the bottom piston will not retract the top piston.
Thank you for your report!
We're tracking this issue in MCPE-87972, so this ticket is being resolved and linked as a duplicate.
That ticket has already been resolved as working as intended, which means this is not considered a bug and won't be fixed. Please do not leave a comment on the linked ticket.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki
-- I am a bot. This action was performed automatically! The ticket was resolved by one of our moderators, and I left this message to give more information to you.