postgres: blocked fetch stream when/after WAL / auto vacuum completed

[gitmalong]

I observed something strange when processing all data from a huge table in a timeframe (1h) within that postgres executes auto vacuum/writes WAL. In my case this always occured short after another so I have not really pinpointed it WAL or auto vacuum.

However my fetch stream does then not continue delivering data, it remains in a blocked state.

postgres 16

Before going to deliver reproducible examples etc. I want to ask if this is a known problem or some other people have already tapped into?