Mount Not Auto-Attacking Turn Based

I have a Vital Strike character mounted on a Dog. Vital Strike is auto-cast enabled. In RTWP the mount attacks with my character. In turn-based when I attack my mounted character will Vital Strike but my mount won’t attack. I have to turn off auto-cast in order to issue my mount an attack command.

Is this a bug or is this intended? I switch between RTWP and Turn combat and it’s really annoying to have to turn on and off Vital Strike from auto-cast.

My apologies I meant to post this in the bug forum.