I had the same issue, but the issue seems to have disappeared sometime in the past week. I don't have a soundbar on the Roku Ultra we use for Amazon Prime channel. Our TV feeds its output to a stereo receiver that feeds the sound to a pair of stereo speakers.
While we had the issue, I found the easiest way to get it back in sync was FF for a couple seconds, pause, then rewind. Alas, whatever they did to fix the issue broke both FF and REW. Both those functions are now essentially dead keys on the remote.
The feature that identified actors on Pause also disappeared yesterday.
Will this channel ever work the same for two weeks running? It is getting ridiculous.