I’d have to say I agree with the original question. The only reason I noticed it is because on some missions my horse magically shows up wherever I end up, and on other missions my horse stays out in the wilderness miles away.
It’s the inconsistency that makes me think “bug,” not “feature,” if that makes sense. If my horse was ALWAYS staying in the middle of nowhere after a mission (sticking to realism) then I’d be all on board. But seeing as it seems to be pretty random...bleh. I don’t agree with your horse sometimes magically ending up where you do after a mission and sometimes not.
Or maybe the horse shows up after “main quests” only? I’m not too far in the game, but my horse has always been where I am after a mission. However, I just did my first bounty hunter quest with Benedict Allbright, and my horse is still out by Benedict’s encampment and I’m in town. The cinematic during the mission had me automatically jumping on Allbright’s horse to chase him in the river, so I assumed the game was going to teleport my horse wherever I ended up.
BUT now that I think about it, for fear that my horse would get spooked on that cliff and dive into the river below, I DID tell it to STAY. So maybe that’s what caused him to literally stay put where he is?? Hmmmmm!! I bet that’s what happened! Let me know if anyone else has tested this!