Bugs from beta versions only.
You need to have enough momentum to do what you want to do left over from the previous turn. You need to be lower in turn order. You have to use the hotkey bar to spam the button as turn order is transitioning. This can be done with movement, skills, anything that can be placed on the hot bar.
Yeah, still happens on beta. Reproducing is fairly simple, and is essentially key mashing once you end your turn. I would assume the only reason it wouldn't work for Dev is the possibility that hosts don't suffer any sort of lag. But since Scias does the server, I'm not sure if that's even relevant.