Does the phrase "disputed land" emphasize being under control, or being a subject in an arguments between countries. Based on dictionaries, both might be correct. As a native what do you make of it?
To me, as a native English speaker, the phrase 'disputed lands' means only lands whose ownership is a subject of dispute between two parties. I would use the phrase to describe the Falklands (with the UK and Argentina the disputants here), or the Crimean Peninsula (with the Ukraine and Russia as the disputants). To me, it doesn't matter for application of the term who actually holds the land; the important thing is that it's being fought over.
If one party has some kind of superior claim to the land, which is obvious to everyone (such as having lived there before the other party had ever heard of the place), but the other party has taken control of it, I would think of that as "occupied land" or "conquered land", not "disputed". This would describe land held under colonial occupations, for example. To me, "disputed" implies that no one's claim to the land is beyond doubt, so I wouldn't say that land held by a colonizing power is "disputed".