After I switched using the proper HeaderView component for the new TableView, see https://bugreports.qt.io/browse/QTBUG-87135 I noticed that one column at the end was missing when I scrolled too fast to the right of the window. The data column was missing, but the headerview could still be dragged, which revealed another column, but the data column was still missing.
The example has 100 rows and 100 columns, one column is hidden and every second column has a red background. So the last column, column "100" should be red.
Seems to me the same problem with dragging the horizontal scrollbar too fast outside the window (see screenshots)