This may be a parity issue  but probably relates to MC-249875. But when you put Allays in a pipe, like in the video, it sometimes has a delay of a few seconds before flying after the blocks and after a while Allays can ignore blocks on the other side of the pipe.

When you put Allays in the pipe, there is sometimes a delay when he flies after the blocks on the other side. For a while he brings blocks from the other side, and after some time he just starts to ignore the blocks that are on the other side of the pipe and just starts flying around the note block or just flies and does not bring blocks.
As you can see in the video Java.mp4

And in the bedrock version, he does everything instantly and without delay.
As you can see in the video Bedrock.mp4