QAbstractItemMode::dataChanged signal is emitted twice when data is edited in a QTableView connected to a QSqlTableModel. Please see attached minimal, compilable demo project for demonstration.

In the demo, please click Browse button first, and select a destination file for the SQLite database, then click on Process button, which will create a table and insert 3 records into the database and populate the model. Then, double click any of the 3 displayed rows and edit the data. As soon as you click away, you will see a message box appear twice, indicating the dataChanged signal was emitted twice. This will happen each time you edit any of the cells.