Device: Samsung Galaxy Tab A
BUG
When a piston or sticky piston is positioned to have over the limit (13 or more) blocks in front of it, it will not extend when powered. That is perfectly normal. (As demonstrated in the 1st picture.) But when you destroy the 13th block to reduce it to 12 blocks, the piston does not extend even though it is still being powered (as demonstrated in 2nd picture.)
This bug renders useless many redstone creations that would work in the PC Edition.
STEPS TO REPRODUCE
1. Place a piston or sticky piston.
2. Place 13 blocks in front of the piston and then power it.
3. While still powering the piston, Destroy the 13th block so that now there are only 12 blocks in front of the piston. As you will see, the piston does not extend even though it is now only 12 blocks in front of it (The highest push able number).
Linked issues
duplicates
Attachments
Comments

Thank you for wasting my time! The behavior you posted not only was from the wrong version, but also is the fundamental base for 50% of the contraptions. You earned my respect for your attempt at breaking redstone communities and provide false information.
Thanks for your report! This is however a Duplicate of MCPE-15476 – If you have not, please use the search function in the future, to see if your bug has already been submitted, as currently over 47% of tickets are being closed as duplicate.