I have seen this happen sporadically. It seems like a bug and is not specific to the Edit widget. I have seen this happen with any widget that uses a text input.
I can confirm that we don't have any bugs/issues related to hotkey/keyboard shortcuts in Web AppBuilder. Best thing to do is try and get some repro steps for us to take a look at.
Hope this helps,
Have you tested whether it's reproducible when the cursor is over the map and not the Edit widget. I've noticed that when I use Ctrl + or - to change the zoom factor of the page itself, if the cursor is on the map, the map itself will zoom, but the page will not.
The issue Jeff and I have noticed is that the map keyboard navigation is not always disabled when entering data into inputs in widget. This sporadic behavior though as normally this is not an issue but sometimes when clicking into a input box and using the numberpad on the keyboard the minus, plus, 8, 4, 6, 2 keys will result in map navigation. It is as if the map fails to release focus or the input control does not receive focus.
What I'm saying is that's easy to reproduce. If I have the mouse in any place but the map (popup, Edit widget, etc) the +/- keys will work as expected. When the mouse is on the map, using the number pad will result in map navigation. I can use the regular number keys, but the +/- keys on the main keyboard will also zoom.
Hmm.. When I have the mouse over the search dijit and use the number pad plus and minus they do not zoom as is expected. But sometimes when you click into a input box in the (lets say) query widget and use the number pad map navigation still occurs.