The only tab I see on the case feeder is too high,(above), the top of the 9mm cases.
I just checked and it seems you're right. It looks like the 9mm cases aren't tall enough to be affected by it. When clearing, I usually just knock out the upside-down case and then watch a primer fall into the "you know what" because of the empty station. Not a big deal either way I suppose. If it was happening often, it would be a royal PITA.