As a consequence the recent parity change present in the latest 1.15 beta consisting of observers not producing a pulse when being placed, observers do not seem to produce a pulse anymore when moved by a piston.
How to reproduce:
1. Place an observer in front of any piston.
2. Power the piston. The observer will not send out a redstone signal as it should after being moved. Redstone activated components will not receive any redstone signal.
Visual reproduction of this issue:
Observers pulsing when moved is an essential mechanic in countless redstone contraptions and has been an established mechanic for years on Java Edition and Bedrock Edition. If this stays in the game all the way to the release, this will break:
-The majority of flying machines
-Countless other redstone contraptions that make use of pistons and observers
Observers not pulsing when being placed is a very welcome parity change. However, they have to pulse when moved by pistons, which they currently do not. If keeping the new parity change and fixing this bug is not an option, a reversal of this new parity change would be preferrable to everyone.