Fast audible "click" when changing songs

I bought a used integrated Peachtree 300Nova last week and am using a BlueSound Node 2 streamer. I purchased a pair of Martin Logan Motion 35XT speakers from a local store to get going, but thinking about a pair of Nola Boxer S3s.

I first set up using a cheap RCA cable between the streamer and the Peachtree and I could change songs in dead silence. I read here on AG that a digital coax connection is superior, so I bought a Belden 1694A coaxial digital audio cable from BlueJeans Cable. The coax connectors are not very tight in the sockets which surprised me. The bigger problem is that this cable connection has introduced a very audible momentary "click" when I change songs on the BlueSound via their iPad interface. I'm not touching or disturbing the equipment which is located in another room.

I have a S/PDIF cable and can try that but I've read it is not as good as the digital coax connection. Or should I revert to the RCA analog cable? But I'd prefer to stay in the digital domain rather than make another DAC / ADC round trip.

Any ideas on why the digital coax cable introduced this momentary click?
S/PDIF is digital coax. It may be configured two ways; with RCA connectors or with 75 ohm BNC terminations.
So an ordinary looking RCA cable may be in fact a digital cable which carries the SPDIF data stream.

The clicking between songs could be the DAC switching between file types; ie, CD quality and hires.
If the switching sound is on every song, you should contact customer service.
I had a Schiit dac that clicked on every song; I sent it back.

Thanks. Yes, S/PDIF is a data link layer protocol as well as a set of physical layer specifications.

I meant I was using S/PDIF with coax and hearing the click. Switching to TOSLINK and the click is gone (as it is not there with the standard RCA patch cable). I suspect the digital coax cable I purchased.
This is an interesting case. Sorry I don't have an answer for you.