This is probably not the most familiar part of Postgres to me, but does it break anything? Or is it just inconsistency in the replication protocol?
A test for the described scenario would be a great addition. And, if it is feasible, provide an example of what would be broken with the way partitioned tables are replicated now.
There is a chance that the replication protocol for partitioned tables needs to be rewritten, and I sincerely hope that I am wrong about this. It seems Alvaro Herrera tried this here [0].