Just as the topic says. Multiple tag searches work fine, but a single tag search for, say, 1041_(pixiv) (the first predicate tag with a negative count in the list, currently) returns only one page of results, whereas the consequent of the alias, 1041_(toshikazu), returns the full 6 pages. Further investigation does confirm that the negative count for the tag is the deciding factor in whether it works or not; predicates with 0 results work fine.
I would make a Trac ticket for this, but it appears to be down, so I'm putting it here so I don't forget.
Updated by Log