It does when a new email transport is created, which is bypassed when a UUID record is present. For these domains that are failing, are they legacy domains that were added in the days of cPanel and/or without an _apnscp_uuid record?
Looking at the one I sent you, no, it has a UUID record.
This is still happening, even just now as I tried to transfer the account I’m having psql issues with.
Transferred to see how the psql stuff was working and the roundcube record was duplicated. Stage 0 completes but stage 1 will fail every time.