I don't think it's a bug. It's because spy ops are random.

If you go back to espionage it will show high or moderate. It's not based on the op type. If you are getting that it means you are right between high and moderate. cheers.

what I suspect it does is it runs the code for spy ops and sees how many succeed in like X ops with these stats between the countries. It will come out 16/20, 15/20 and 14/20 all because of randomness and that could be the difference between high and moderate.