If a player jumps on moving blocks, they're frequently pulled back to their previous location. From what I've tested, this only occurs on flying machines, and happens about every 1/4 times you jump.

Steps to Reproduce:
1. Make a piston flying machine (Refer to the attachment for an example)
2. Attach solid blocks to the machine and try jumping

Observed Results:
The player gets jerked back to their previous position on the machine every few jumps, although it can be inconsistent.

Expected Results:
The player should be able to jump freely on the flying machine without issue.

Extra Information
This issue has persisted since as far back as the 1.19.83 Hotfix, and was also mentioned in the comments of MCPE-171680. My friend on Windows recorded this issue, but I can confirm it affects all platforms on Bedrock.