First call GM and ask if you still have a powertrain warranty. The warranty starts on the day the vehicle is put into service, not the date of manufacture.
The problem you have could be as simple as a loose wire. Take a look at the wires and the plugs going to these solenoid valves, maybe you’ll find the problem. Using the OLM is fine and you appear to be changing the oil often enough. The solenoid valves are cheap enough at the dealer and I suspect the aftermarket valves are made by the same supplier. I wouldn’t hesitate to use any of them. This is an easy job.