To reproduce, run the nano browser example and add a keydown handler using DevTools with e.g.
Then, click on the page and try pressing the Ctrl key. You should see that the browser believes that the Meta key was pressed instead (although, surprisingly, it correctly notes the ctrlKey property on the event). A similar mixup happens with a bare Meta keypress.
Note that while the keyCode and key properties are incorrectly set, the appropriate modifier property (ctrlKey, metaKey) is set appropriately in each case.
Possibly related to https://bugreports.qt.io/browse/QTBUG-69442?