By the way, and not using a braille display, when I wanted to get the date announced when NVDA was running I did hold down NVDA then hit F12 twice in rapid succession.
The original post makes me think that NVDA+F12,NVDA+F12 was being pressed twice in rapid succession. I used NVDA+F12 followed by just F12 in rapid succession, never releasing the NVDA key before both F12s were pressed. I got the Save dialog in word, or the show elements panel in Brave, if I did NVDA+F12, released NVDA and then hit F12 again quickly. But never when I depress NVDA, keep it held, and then hit two F12s in rapid succession before releasing NVDA.
Brian - Windows 10 Pro, 64-Bit, Version 1909, Build 18363
Power is being told you're not loved and not being destroyed by it.