Exception thrown: 'System.IndexOutOfRangeException' in System.Data.dll

[ap0405140]

.net framework 4.8+entity framework 6.4.4

Codes:
List xx;

tsql = "select....";
var xxxx = DB.Database.SqlQuery(tsql);
xx = xxxx.ToList();

Result:
variable xx can get a list, but some error in Output Window:
Exception thrown: 'System.IndexOutOfRangeException' in System.Data.dll
Exception thrown: 'System.IndexOutOfRangeException' in System.Data.dll
Exception thrown: 'System.IndexOutOfRangeException' in System.Data.dll

this error cause by last statement(xx = xxxx.ToList();), why?

[ajcvickers]

This issue has been closed because EF6 is no longer being actively developed. We are instead focusing on stability of the codebase, which means we will only make changes to address security issues. See the repo README for more information.