The next time it happens, please PM me the exact deck you're using and we'll try doing some testing using those cards, as it might be related to a specific card you're using.
The AI uses some heuristics to perform actions. Sometimes it doesn't play every card as soon as it can by design. This might look like it's not doing the right thing, but according to it's calculations, it's not doing something for a reason (although I cannot explain this specific process or reason). E.g., I saw the AI trade a card when it had a divine shield card to play. Ideally, sure, it would have been better to divine shield and then trade, but according to the AI calcs, it was better to save the card. It doesn't mean the AI did something wrong per-se, it's just the cacls it did lead it to think it would have been better not to use it.
As users send us more logs and issues, we'll try to make more changes and double check to make sure we're not breaking anything specifically, but it'll take some time, as it's impossible to test all scenarios and card combinations for possible side effects or breakdowns in logic that result from any changes.