Attempting to move an add-on user into a new group causes misleading error

Problem Definition

When a customer attempts to modify a system user (including to move an add-on user into a group) an error occurs.

System users product access cannot be removed

Suggested Solution

This is misleading since the user is not trying to remove access, but just add them to a new group. The cause of this error is that customers are not able to modify system users in any way.

Perhaps we can modify the error message to tell them that they're not able to modify system users, not that you can't remove access.

Why this is important

For clarity!

Workaround

Generally it shouldn't be necessary to move an add-on user to a new group, but if it's required to work then you can contact Support to do so.