Naturally I thought it was the bottom door gasket. I changed that out along with the upper door gasket, both easy to do and AppliancePartsPros got the parts to me fast. This worked for a while and then I noticed the DW was leaking again, this time from the float switch. Again an easy fix and APP got me the parts right away. Another week or two and the leak reappeared under the door and occasionally around the float switch! Grrrr!
Figured it might be a defective spray arm. I could not see anything wrong with it but decided to change it out anyway. APP came through again and this time it appears that the problem is solved. It seemed the old spray arm must have had a crack that allowed it to shoot high pressure wash water directly at the bottom door gasket and nearby float switch, conditions neither of them are designed to handle.
Also this particular bottom door gasket can't be installed with "the bottom lip facing downward" as they tell you to do in the repair videos unless you put a new notch in its opposite end. At first I ignored the video and installed it with the lip tipped up per the factory part. At one point in desperation I notched the other end using a template to exactly locate and precisely cut the notch in the opposite end so that I could install that gasket lip down. Lip down after modification worked 10 times better than factory even with the defective spray arm!
Thanks, AppliancePartsPros. Great service and very helpful repair videos!