IMO, it is not a bug. It is, however, a mystery.
There is more involved in battlefield intel than just encryption/decryption. Unfortunately the game doesn't even give us any good hints as to what that is.
Recon companies may be a factor. Weather may play a part as well. Whatever it is the calculation seems to be world wide and not local. It also seems to be something that is calculated per nation. There could be a random element to it. The two factors I listed earlier both seem to make sense only locally but who knows if some sort of cumulative score (+RNG) is taking place.
Whatever it is does not shift often. You don't see them and not again a few times a month. I have seen this status flip when no apparent actions took place, as in neither side finished research or modified templates.
I don't think this is broken, but we do need more feedback on this and other game mechanics. There are too many things that we are asked to take on faith. Considering the track record of bugs in this and other games of similar complexity, it is no wonder that our faith wears thin at times.