Non-administrator roles assigned with any administrator-level privileges are unable to configure apps from ArcGIS Instant Apps shared with them in a shared update group.
Use another app builder platform which does not exhibit this issue, such as ArcGIS Web AppBuilder.
Change the ownership of the Instant App to the specific user. This enables the user to configure the app.
Change the user role to one which does not exhibit this issue, such as the default Administrator (If administrator privileges are required), Publisher, or a custom role without any administrator privileges (If administrator privileges are not required).
Change the custom role privilege settings to remove any administrator-level privileges.