Mini Aussies are not akc recognized, I think, unless that recently, but they can be shown in the iabca (international American breed club ??) basically, they are mostly just Australian shepherds that are selectively bred for smal size.... The akc standard lists Australian shepherds should be 18-23", GSD's should be 22-26" depending on gender
Unfortunately, when breeders breed for only one trait(size for instance) many of the other traits that make Australian shepherds what they are get thrown to the wayside..... Of course, not all of the mini Aussies are this way, but enough are that they can't all be depended on to have a specific temperament or working ability.....
But this is what happens when any breeding program focus' on looks alone, and not on temperament or ability
P.s. I feel a little repetitive... Lol... But it is hard to edit on the phone with one finger 'typing'