This has been a pain for the last 12 months, Q to O failing.
My solution is to hold down the Q key whilst tapping the other affected keys (W to O). It usually brings them all back to life after a few taps.
You can also hold down the Q key and tap a single affected key on its own, for a quick one-key solution.
Q to O will eventually fail again, but using the above always brings them back.