Hi @DaveToo
Welcome to the Sonos Community!
Sorry to hear of this issue you are having with your Amp not completing some songs.
In all likelihood, this will be caused by interference. If there are any WiFi devices near (within 1m or 3 feet) of the Amp, please remove them. Likewise for the router.
Please also see our Reduce wireless interference help page for more advice.
If you continue to see such issues after moving devices, or if there are no devices to move, I recommend you get in touch with our technical support team who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports.
I hope this helps.
"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein