Hi tnprime,
I’m afraid “Change the freewheel and hear if the noise is gone” is not that what you wanted to read…
But that’s what I’d do; I mean there is still much room for snacks…
Maybe too much belt tension?
Oh yes (if you mean crackling noise)!
I bet this is exactly the Strida 5.0 “clicking” noise
And if you mean a rattling noise: That’s the rear brake cable inside the frame.