I too have noticed seemingly random moments where a turn is skipped. Additionally, I tried to stay vigilant in watching for any stuns, freeze, charm, etc that would be possibly affecting the situation.
It does seem partially related to the 'shared turn' concept (which I do think is really cool, especially in Multiplayer). Something that would really help is a rudimentary combat log or way to see something I may have missed. The turns can move at a jarring pace (6 seconds of CPU thinking, then 3 quick actions in 1 second) kind of stuff.
With how prevalent the issue is, it's likely they're aware of it. Nothing less fun in a game than losing control (or losing out) on a whole turn of choices!
