I'm not sure what you would have been aware of as at least physically there is no movement during ECT treatment except usually one toe so they can see that the seizure is happening. I would guess you could certainly have a dream during the treatment. I don't have any idea if I dreamed or not, but I generally don't remember my dreams anyway.

Have you contacted the treating psychiatrist with your concerns? They are the ones who have dealt with many patients over time so he might be able to tell you if this happens sometimes.