Yes.
If the customer already has an MDM profile in iOS device that means that the harmony Mobile MDIS cannot be installed (iOS can have only one MDM profile) there are 2 options:
1. Integrated that MDM with Harmony Mobile (setting > integrations >Add MDM)
2. The option you suggested (screenshot) to disable the MDIS push into iOS devices protected with HM
option #2 is relevant usually when there is no MDM integration Out-of-the-box
please note that without MDIS or MDM integration working there is no way to read the list of applications from the iOS device protected by Harmony Mobile. Other protections work of course.
Yuval