Inspection of the suspension rods and springs looked good. Two of the absorbers (AP4539663) were missing and the other two were damaged. Ordered new absorbers. Very disappointed in the price for four little strips of foam tape. Did not fix the issue.
More research into parts per symptom kept indicating the suspension spring kit. I had little faith that would fix it because the originals looked OK. Reluctantly ordered the suspension springs. Installation was difficult due to the location of the washer. I was able to slide it out just a few inches so it could be tiled just enough to reach under to replace the front two. Removing the back cover allowed access to the right rear, but not the right-left. Replaced the right rear. Due to the limited access, I used a set of bolt cutters to cut the rod making it removable. I used a strong twine to pull the rod up for installing the top pieces. Finally got it all done. Would have been much faster and easier if I had more room - access to all four corners.
I still did not expect any improvement. The first load went perfectly. Still a little doubtful, but now after about seven or eight loads and everything working perfectly, I'm happily convinced. Still a bit of a mystery. Comparing the old with the new does not indicate any obvious difference. Even the spring strength and length seemed the same. In any event, that was the issue.
I checked a 2 for challenging only because of the washers location, not the actual repair difficulty.