I've noticed two distinct issues while leveling Beastmaster and believe they are unintended behavior.

#1 Currently, if you have trust NPCs summoned, you can NEVER use the Tame ability. I have only been able to use this ability with NO trust NPCs summoned.

#2 If your pet becomes uncharmed and you successfully recharm it, you cannot summon/resummon trust NPCs until you dismiss the pet, the pet dies, or you kill another monster. If you have a charmed pet, the enmity should be gone and therefore you should be able to use Trust magic.