Option + Delete stopped working on OneNote for Mac

I use Microsoft OneNote every day on multiple devices: 2 Mac laptops, an Android device, and an iPad. I love it.

But sometime in June 2016, about 3 weeks ago, the keyboard shortcut to delete the entire word preceding the cursor, Option + Delete, stopped working. It only stopped working on my 2 Mac laptops — it continues to work fine on my iPad (for which I use an external keyboard).

I’ve Googled and emailed OneNote tech support, but haven’t turned anything up or received a response.

Has anyone else experienced this?