I have a 2020 36ssws and it to developed the crack shortly after purchase
I towed it to Vogt RV in Fort Worth TX and they cut out a section of the sidewall, welded aluminum gussets to reinforce the area and patched it back in and had the area repainted as it have full body paint. this season it developed a crack again and I am again taking it back under warranty to have it repaired and the expantion joint installed after repairs are made