There were new click and mouseover functions added in 9.2. You may want to take a look at the options under Interface Options → Combat and see if adjusting them helps your problem. I have not tried to use these features yet personally, and I also don’t think I’ve had any issues with healing with the standard raid frames.
This was a potential workaround mentioned by another player in a tech support thread about raid frame delays by going into the options I mentioned above: