Classic Why do some battle pets auto resummon after flying and others don't?

So I've been searching around online but can't find any info on this.Most of my Chars have a specific battle pet summoned to follow them around. Now some will auto resummon after using a flying mount and others don't.I thought originally it was down to pets who can fly stay/resummon and the ones who can't you have to manually do it.However, my Warlock, for instance uses the Corefire Imp as his pet, which obviously isn't flying. Whenever I fly and then dismount it's always resummoned but my Death Knight uses Boneshard and I have to manually resummon it after each dismount, same for my Shamans Spirit of the Spring.Anyone got any ideas on why this is? Not really important just a bit baffling. Xx via /r/wow https://ift.tt/EPrMfRu