Cannot assign members to Collection because is greyed out
Unable to add a new System to a Collection because the Assigned and Unassigned buttons are grayed out
When a Collection is being managed by an Auto Discovery Mapping, it is not possible to manually edit the member list for this Collection. The members will be automatically managed by the Mapping. This is by design and there is no workaround to change this
It will be necessary to create a new separate Collection that is not associated with an Auto Discovery Mapping. Then it will be possible to add and remove members to this new Collection.