This is the 2nd time this has happened using normal cycle with heated dry about 3 years apart. Ordered a new lower basket with roller assembly, and most all the plastic interior compartment parts. Received parts fairly quickly in 3 separate shipments within a week.
Only took about a half hour to remove all the damaged parts, clean the bottom of the interior cabinet and heating element of melted plastic and install the new parts, a fairly easy fix. We will not use the heated dry option anymore. My guess is that a knife blade fell through the utensil basket and shorted across the heating element and probably jammed the lower spray arm from spinning, this caused excessive heat, so hot you could not even touch any metal items without getting burned, had to wait for it to cool down to remove items that melted all the plastic parts, any plastic bowls and handles of knives that were being washed to melt.
Wife reported, now works better than ever, dishes seem to come out cleaner, dryer than before.
Thanks to Appliance Pro for the great and accurate filling of my order,