Seaquel
SQL Server error code

SQL Server error 5334

SQL Server raises error 5334 at severity 16, which marks a problem with the query or data that you can correct.

The identifier '%.*ls' cannot be bound. Only target columns and columns in the clause scope are allowed in the 'WHEN NOT MATCHED BY SOURCE' clause of a MERGE statement.
Msg5334
Severity16
Group5000–5999

Source: Database Engine events and errors