If the Focusrite would be the problem, then Focusrite would have to acknowledge this. Roon Labs would only comment on their own product and not acknowledge anything if it’s not their fault.
In the thread below another forum user even used a test file and could confirm that Roon doesn’t “play” pops. While his theory is a possibility for the source of some audible pops in a users system, she doesn’t explain the loud pops on stream start or the less loud pops in the silence between tracks at all. Sadly my theory also doesn’t explain the later. Good luck with your testing, I really hope you can find some answers.