Put the summary of the bug you're having here
I tried to make one of those automatic cactus farms in MCPE with the introduction of water buckets I expected he cactus to pop out when it grows beside a block but didn't.
The cactus grows beside the block until I give it a block update which made it pop off.
Place a cactus with a block diagonally above it. Wait for it to grow and you will see that it does ot pop off until you update it.
Duplicate of MCPE-3039, please use the search function to see if your bug has already been submitted. Currently over 60% of tickets are being closed as duplicate.