I don't share the opinion of calling it "successful"
Looking into the write log it clearly says it archived incompletely
You cannot expect that the whole master data is deleted if you still have it referenced in existing documents.
SAP further says in the deletion log that it adjusted the validity period, probably closed it with a past date so that this cost center cannot be used in new documents anymore.
This part will be archived and deleted after you archived and deleted your documents where this cost center is used.