I'm not sure if this is a bug/glitch or something I screwed up, but I have this NPC, who just attacks everything in sight (except me). It attacks even my dismissed followers (but ONLY once dismissed).

The factions the NPC is in are:
-1 Current Follower
0 Potential Follower
0 Potential Marriage
0 Town Falkreath

Relationship level is ally, "Parent" = Player, "Child" = NPC, no association type. Disposition 75.

NPC is set to "Unaggressive."