Automatic MDM enrollment after EC version upgrade - how to prevent?

After upgrading to EC build 11.2.2300.11 with the enterprise version license, some of our laptops have started automatically enrolling in the ME MDM. How can we prevent this? We utilize the EC Agent on all our machines in conjunction with Microsoft Intune as our full-fledged MDM solution. We only want Intune enrollment on our machines as the MDM -- is there some setting I'm missing to shut off Endpoint Central MDM enrollment altogether? On machines we are setting up fresh, once the GPO applies and the EC agent installs, the machines appear to try to ME MDM enroll if they haven't yet gotten Intune enrolled. Worried this will become a larger issue if we don't fix this now. Generally just want to block MDM in Endpoint Central altogether.

Thanks