Since the early morning 11/14 update to my Roku Ultra, the play/pause button (doesn't seem to matter if I use the actual play/pause button or the OK button) seems to be really sluggish. It takes 20 or 30 seconds before it responds to a play or pause command. When you first press it, and you think it didn't work, then you press it another time or two before anything happens. The multiple button presses often cause havoc. The directional controls on the home screen don't seem to be affected.
Have you tried rebooting your wireless network to see if that helps the issue you are seeing?
If you are still unable to resolve the issue, please send me a PM with your Roku account email address, and include the serial number of the Roku device from Settings>System>About along with a summary of the issue you are experiencing. I'll be able to assist you further from there.