iPad Smart Keyboard — delete key not working

A handful of times recently, my delete key has stopped working when typing both in a Facebook field and in MS Word. Other keys would work. I’ll detach and reattach the keyboard to no avail. Obviously, detaching and restarting are not permanent solutions. Is this a common problem?

On a few of these occasions, the screen stops responding to touch... yet even then, other keys work.

—Chuckletrousers