Multiple table joins

Your joins are linking A.widgetID to B.tagID, whereas they need to be A.widgetID to B.widgetID (linking to the foreign key). Otherwise you'll be linking data arbitrarily.

Try updating your joins to all link to the foreign key, rather than the primary.

PS: The reason you may have seen the tags join working (although it is incorrect) may just be due to lack of test data/variety. Your tagID's likely were the same as the widgetID in your test case.