Measure the height of each rear tire when inflated to proper pressure. I'm betting that you have one rear tire that is slightly larger than the other. Pretty common.
If that's the case, lower the loader/bucket flat to the floor in float position and relax (loosen) the loader mounting bolts. Re-tighten mounting bolts after the loader settles.
The loader sits flat when in float mode. When not in float mode is where I see the difference.
The floor is level. In the picture I posted there were two levels, one on the floor. I have a plastic floor tile system (swisstrax). The dealer asked about it when I sent them the picture. It is not “compressible” and is not responsible for the difference. I measured in several locations around the garage and on my not exactly flat driveway (paved).
I do think the tires are slightly different sizes. The dealer mentioned this as well, that they are sometimes a bit off from each other. I think it may be some from the rear and some from the front and swapping them just minimized the difference. They also talked about possibly loosening up and adjusting the frame as a possible additional measure if I was still unsatisfied.
So far, with it now about 1/2” I’m going to give it a go.
How level or not are your loaders. Measured when the bucket is flat and an inch or so off the ground (not in float mode)?