I have an app that scans VINs and looks up the vehicle info and shows me the available parts at the auto parts store. If I install it from the App Store it shows up in Settings and when I launch it it asks for permission to use the camera. Everything works fine. If I make it available in Self Service and use VPP, it installs but is not in Settings and never asks for camera permission. Since it doesn't ask for permission, the camera doesn't work and I can't scan my VINs. Any ideas why the app would act different? Is it a Self Service thing? Is it a VPP thing?
Did the machine it is installed on get its current enrollment via DEP or a method that satisfies UAMDM?
On High Sierra and newer versions of macOS, the enrollment method matters in regards to what MDM features you can use. It is possible that macOS might distinguish between an app installed with human intervention, and one pushed by an MDM. If you do have a configuration meeting the DEP/UAMDM requirements, have you tried pushing a privacy preferences policy mobileconfig to allow the camera for that app?