Kitchenaid dishwasher thermal fuse keeps blowing

My Kitchen Aid, KUDS02FRSS0, dishwasher keeps blowing its thermal fuse. I’ve replaced it several times and used the extended wiring they supply with the new fuse. I’ve also replaced the heating element, thinking it might be over heating the unit. The fuse still blows out. It takes a couple of months to happen. When I replace the fuse the unit works fine for another couple of months.

Does anyone have any ideas what is wrong?

Keith