Game Mechanics: you must be standing to cast a spell

[Caravelle1]

Got a bug in a crucial PvP moment. had an earth pet on me, and got magic nuked. Got a "you must be standing to cast a spell" for 15 seconds even though I was clearly standing.
Anyone else have this?

[Verdu]

What terrain were you around?

I've been knocked back before into an area that auto-ducks me. Like if you clip a big rock or tree it will duck you until you move away and then after a bit of time you will re-stand.

[Truth]

turn off autoduck