Seaquel
SQL Server error code

SQL Server error 9525

SQL Server raises error 9525 at severity 16, which marks a problem with the query or data that you can correct.

The XML content that is supplied for the sparse column set '%.*ls' contains duplicate references to the column '%.*ls'. A column can only be referenced once in XML content supplied to a sparse column set.
Msg9525
Severity16
Group9000–9999

Source: Database Engine events and errors