Under ADODB, the Connection.OpenSchema method returns a server-side static recordset. Conversely, the ADOLibrary version of this method returns a client-side recordset. This detail is by-design and shouldn’t be considered as a bug.
The reason for this difference is as follows: ADOLibrary doesn’t support server-side static recordsets (except for SQL Server) and returning a server-side forwardonly-readonly recordset would have made the recordset not navigable (i.e. the MovePrevious method would have thrown an exception).
In practice, this detail shouldn’t cause any problem in the migration of a VB6 project.