In version 1.14 of WoW Classic, we intentionally implemented the automatic-dismount when casting a spell or interacting with an object, as a quality of life improvement.
For the time being, if you’d like to disable this, it is possible to do so via CVar commands.
The commands look like this –
/script C_CVar.SetCVar(“autoStand”, 0);
/script C_CVar.SetCVar(“autoDismount”, 0);
/script C_CVar.SetCVar(“autoUnshift”, 0);
– where 0 disables the function, and a value of 1 would enable it.
We’re looking into making this an interface toggle setting in a future version of WoW Classic.