What could be the reason for reverting changes in postgresql?

Question

PostgreSQL

ASP .NET Core project. In it I use postgresql + linq2db. Changes made to the database are canceled with varying frequency. Approximately this is how all changes in the database are made. What could be the reason?

using (Context db = new Context ())
 {
   db.SomeTable.Where(x => x.id == 1)
      .Set(x => x.Status, "done")
      .Update();
 }