Sorry for my English, not native speaker.
I suppose, Russian-language tech. support isn’t working, that’s why in-game support are not answering me. So here we go.
When skyriding is active: favourites button summons skyriding-capable mount in location, where flying is doable.
When activate steady flying AND character does not move after switching: character continue summoning flying mounts
When steady flying is active AND i fly some distance: favourite button summons all my favourite mounts, ground mounts included.
It workes vice versa.
I capture some video with this bug:
(https://youtu.be/YChW3FMOJGs)