Does anyone else ever see this? I call it 'leopard print' in the stress result.
Stresses in the main horizontal members and in the L-shapes which come off of them are continuous and monotonic, as expected.
In the vertical beams and the frame which rolls inside them the results are splotchy and mixed. Checking some of the resultant forces I also find impossible imbalances.
I see this sometimes in an assembly with contact, usually after I "duplicate" a scenario. The only fix I've found is to delete all the contact pairs and remake them.
In this case, it is a brand new model and new simulation setup. I duplicated the setup, remade the contacts between the vertical members and the inner frame, but got the the same result.