Running ZCM 11.2.3a - having to install an MSI that requires elevated rights during installation (user are of course not local admins)

Issue is that when the installation is set use the User and "Grant administrator privi..." is ticked, we get a validation prompt (blue Zenworks box) reuqesting to type in the user password twixe. After that the install completes fine.

Includiing the same user in the local administrators group and unticking the "Grant..." result in a succesfull install withuot prompts as expected.

Here is the clincher: As a local admin with the "Grant..." enabled we do get the password prompt again, and after entering password it installs fine.

So what "prompts" Zenworks to popup and ask for password ?

Any ideas ?