Immediately apologize for the bad English, it is not my native language
I have a slightly different problem - after updating to 2.04.13 is no sound when playing MP3 and any video files containing audio in MPEG
In this case, flac and ogg - play normally, mkv c 5.1 audio (like DTS), also without problems.
Manual adjustment of audio output formats (choose Dolby and DTS over HDMI) has not solved the problem.
If you select stereo mode, the sound is played through all the files, but it is not the solution.
Rollback to previous firmware version (2.03.24) eliminated the problem