Frostcrag portal doesn't teleport horse?

[ParanoidAndroid]

Not sure if my game is bugging out or if it always worked this way but here it is. In Frostcrag Spire I use the teleport portals to teleport to one of the mages guilds. I thought my horse would be teleported as well, which is also stated in the uesp wiki. However, my horse remains at Frostcrag for some reason. Maybe it's because the horse is armored and according to the wiki, armored horses stay where they are? When I walk outside the mages guild to the stables, my horse is nowhere to be found. But when I fast travel to the stables (where I'm standing), my horse appears.

[Imbalance]

I'm gonna say it won't work, but I can't even figure out how you got the horse up there.

[ParanoidAndroid]

The horse is waiting outside Frostcrag. When I use the portals I'm not mounted but according to the wiki the horse should move to the stables, just like when fast travelling.