Well usually with females, the conflicts are early, then they settle down. Males it goes from wow buddies - to wait a minute- who is boss here??!!
I would still check the anal glades to rule out a musk. Especially since they get along better after they have been out ( explosion so to speak..... ... .. ).. And the arguements occur more if they have been in the house for a while ( non expulsion so to speak.. .. ... )