I have exactly the same DP - both the light bump as the wheel goes round (more noticeable at slower speeds) - and the noise from clipping the plastic cover.And grinds
Edit. There is something not quite right about the riding experience. There is a very light bump bump of the trainer going around. I thought it was an untrue wheel but when I got a new one there was the same issue.
The grinding was the fan blades on the trainer next to the metal disc. A clip broke and it was clipping the round plastic cover.
I never did work out what was causing the "bump" thing but AAAC may well be right about a slight bulge in the tyre from the innertube