Seaquel
SQL Server error code

SQL Server error 2531

SQL Server raises error 2531 at severity 16, which marks a problem with the query or data that you can correct.

Table error: object ID %d, index ID %d, partition ID %I64d, alloc unit ID %I64d (type %.*ls) B-tree level mismatch, page %S_PGID. Level %d does not match level %d from the previous %S_PGID.
Msg2531
Severity16
Group2000–2999

Source: Database Engine events and errors