could it be Dropouts, check this article to see if it fits your issue:
Instead of holding up the audio hardware to wait for the late-to-arrive data, RAAT outputs replace the missing data with silence and continues with playback.
Is it only Qobuz content that’s problematic and local files play without these problems I would look at your internet connection? Also use the troubleshooting guide as recommended earlier.
Hello @Terry_Bradshaw, if you aren’t able to play to system output, could you please try disabling your antivirus/firewall and playing to system output again? Let me know if this makes a difference. Also, does the core connect directly to the router or is there anything in between?