[AndreaWozzup]

Dunno if my impression is correct, hope anyway I explained the issue.

Your impression is correct.  That audio profile change is triggered when Kodi sends an OnPlaybackStarted event.  I don't know why Kodi isn't sending that event when you start playback in your use case, but that's the issue you need to figure out.  There is no work around on the audio profile side for that.

Thanks for replying
I think Kodi is sending the event, because the audio profile change happens, it's just that is sent after the playback is already started, so I think the audio playback starts on DIGITAL (HDMI) and then audio output config is changed to ANALOG (usb) and this cause the hiccup on Kodi default audio player (paPlayer? I see that from the logs I tried collect https://paste.libreelec.tv/new-sunbird.log).
Maybe paPlayer can't handle gracefully a switch of audio output? Or at least that what happens on the Rpi5, which is after all something recent..

I know is a lot to ask here, since it's not an add on issue, but I have no idea on how to investigate it further (which is not really a deal breaker, just... strange ), can you suggest something (i.e. which log to collect etc)?