Test Case:

I was using a model returned by QTableWidget::model and inserted two rows of QVariant data of type 'bool' to the UserData role. (I also set a string to their Display role.)

Immediately before calling setData, I confirm and assert that the userType of the data I am setting is 'bool' (typeID=1)

Immediately after calling setData on the second row (row=1 col=0), the data which is returned by model->index(1, 0).data(Qt::UserData) now shows a userType of 'int' (typeID=2).

Note: this does not happen on all program runs. It happens sporadically on some program runs. You have to completely shut down and restart. When it's happening, it is repeatable during that program run.