New mkv format corrupting audio

Hi. Well I’ve been using the DVR for nearly a year now, but since the latest update(s) I’m getting mixed results. I record a drama each week, 2 weeks ago the update to ‘live’ changed the recording format to mkv, but apart from losing the subtitles, it was fine - full HD and 6 channel audio. Last week, the audio only recorded in 2 channels, this week no audio recorded at all.
Has anyone else had this issue? I’ve attached media info for the 3 weeks recordings.



Server running Version 1.7.3.3937 and connected to HDHomeRun.
btw. Also have NextPVR running and that’s recorded the same show without any issues with sound as a .ts file.