Noticed the lower arm of the dishwasher was in the same spot several washes in a row, so I got suspicious of the gap between that top nut and the arm. It looked like a lot of water could slip past. I found a small washer that fit almost perfectly in a junk box in the garage and now it seems to be working better.
Because of course it’s a dishwasher, this happened
So I bought an assortment of nylon washers then washered my washer again and it seems to be doing well.