2535897 - Msg 17549: "you cannot drop user. The user has granted the following privileges" - SAP ASE

When trying to drop a user using sp_dropuser it is returning message 17549:

sp_dropuser user1
go
Msg 17549, Level 16, State 1:
Server 'ASE', Procedure 'sp_dropuser', Line 355:
You cannot drop user because user 'user1' owns grantable privileges and
granted them to other users.  The user has granted the following privileges:

 grantee                          object
         column                   privilege
 -------------------------------- ------------------------
         ------------------------ ------------------------------------
 user2                         titles
         All                      Select

(215 rows affected)

User 'user1 was granted grantable privileges by the following users:
 grantor
 ------------------------------
 dbo
(return status = 1)

• SAP Adaptive Server Enterprise (ASE) 15.7
• SAP Adaptive Server Enterprise (ASE) 16.0

login, permissions, object, revoke grantee, unable to drop , KBA , BC-SYB-ASE , Sybase ASE Database Platform (non Business Suite) , Problem