This seems to have resulted in stray house tags being added to nodes, in addition to areas (e.g. at the corners of a house).

Also FYI the wiki page for mapping houses recommends "house=semi-detached"  or  "building=semidetached_house", but I don't see any mention of "house=semi_detached". I could be out of the loop, I'm assuming the wiki is up to date on this.
https://wiki.openstreetmap.org/wiki/Key:house