[RWP] NVDA and Reaper Key Conflict?

[Indigo]

I just installed Reaper 4.721 x64 on this just repaired Acer desktop, 
and noticed something I don't remember before.
I had the OCR addOn installed in NVDA, but when I tried to use NVDA's 
screen review, without having hit NumPad insert+R to turn on OCR,  to 
look at Reaper's screen, I heard nothing.
When I pressed NumPad insert+R to turn OCR on, I heard a dialog that I 
had no track armed for recording, as if I had pressed the R key alone to 
record on the selected track.
I removed the OCR addOn and now NVDA's screen review works normally in 
Reaper 4721, letting me view the usual stuff that's on Reaper's screen.
What is going on?
Once you press NVDA key+R to switch on the OCR function, is there a 
shortcut to switch off the OCR function, or does it remain on in NVDA, 
even after rebooting?
Thanks,
Indi