Shortcuts won't work on Mac (the esc and left/right arrows)

For some reason lately, every other time exiting a photo with the esc key on my Mac just doesn’t work and beeps at me; same with moving over to a different photo with the arrows beep at me. But the other shortcuts work perfectly fine. 

The only way to fix this is when I restart the app—but that’s no fun every time.

Thanks

version 9.3.1