In case it's unclear what was done here: Mission Creek Senior was previously a multipolygon relation/3830966 with a single outer way/288649887. That way was edited (changeset/185651579) to also contain tags for the SFPL Mission Bay Branch Library, duplicating the existing node/317124778 (which was incorrect; the library does not span the entire building). I removed the redundant multipolygon relation, removed the duplicate library tags from the way, and moved the relation's tags (for Mission Creek Senior) onto the way.