Vierd log entries: "exception: Failed to read mixer for 'alsa': no such mixer control: PCM"

Volumio ver: 3.449
Raspberry Pi3B+
Raspberry Pi DAC Pro (I2S)

So, it appears in the log before every new audio file has been played: "exception: Failed to read mixer for ‘alsa’: no such mixer control: PCM" So what does it mean, should I be worry for anything? (Audio plays fine BTW, but it’s strange and would like to know hat it supposed to indicate technically).

Thanks for the answers!