Chagrins

Originally the issue started out small, just a weird noise like something was rolling over a bump making a thump sound each time. It only occurred when the print head was on the right side of the printer, anywhere past the center. It has progressively gotten worse, now to the point where it's starting to slightly deform prints and it doesn't seem to be in a consistent spot. It can happen for like 5 to 10 layers, then never happen the rest of the print. I've checked belt tension and everything there seems okay. I'm worried that it could be wear on the belts, it is 3 years old as this was originally a UM2 and I've done the upgrade kit. Also a note, not sure if it's related but I want to lay it all out there. When I calibrate, the step where you use the piece of paper, I either get a near full stop, where the head is pressing firmly against the glass plate or it's too loose and the paper can easily slide in and out without any friction from the head. This started after the UM2+ upgrade was added. Edit: I was messing with the calibration and instead of measuring it as close to the 1mm that is recommended on the first step, I went just a notch above. Then during the fine tune part of the calibration, I was able to get a more concise calibration, with somewhere in the middle of what I was getting. This seems to have stopped the noise as I've been printing for the last 4 hours and not heard it.