A new 'bug' I have encountered since the last update - sometimes (not every time) after watching a recording, deleting it, and returning to live Freeview, there is no audio and the video is stuck in a 2 or 3 second loop. Changing channels cures the video, but not the audio. Switching to standby and back on doesn't cure it, but watching a recording and then stopping it, does!
Yes, we’ve encountered this too. I was baffled by it at first, but as you say the only way to get the audio back seems to be by watching a recording. The first time it happened to us my O/H was watching a recording and stopped it without deleting, with the intention of returned to it later so that we could watch something together, and the audio just disappeared. We solved it by returning to the undeleted programme for a few seconds and the audio returned so that we were then able to watch something else together.