Follow up: Never did find a clear cause but I suspect that it was as you said, too much detergent, maybe even the wrong kind (not HE). I had a renter...
Took a chance and replaced the cold water inlet valve. That fixed the problem. Must have been the original mold/mildew blockage that caused the valve...
Hello, This thread is old but I imagine people are still having the same problem. I did, and I ordered a replacement HV board from a local appliance...
