ent8r
The housenumber quest will never popup for a building tagged only with "building=yes". Those elements are filtered out because there might be too many false-positives...
I already started to implement a new quest for specifying the exact building value for buildings tagged only with "building=yes".
The Pull Request for this quest can bbe found at https://github.com/westnordost/StreetComplete/pull/774 and it is planned to be implemented in v5, the next major release...