If the off position on the thermostat is changing you need to replace the thermostat and most likely the knob.
Please check the model number, the one you provided is not coming up.
Find Appliance Parts at AppliancePartsPros.com - Largest inventory in the U.S. with 91% of all in-stock orders delivered within 2 business days. Thousands of photos and diagrams make it very easy to find the right part. Enter your appliance model here.