Only the Service Desk transaction can lock/unlock issue for Urgent Change

Hi Experts,

We can't remove the task list lock for urgent change and face following error "Only the Service Desk transaction can lock/unlock".

There is a SAP note (2484495) relevant to this issue and we already checked it however task list still can not unlocked via CM_ADM_COCKPIT. We are using "(SMIM)" as phase cycle.

Do you have any idea how to overcome this issue? Is this SAP standard?

Thank you

Mertkan Poyraz