Yeah I guess in retrospect that must have been it, though at the time I took it as him closing in on the lion.
Given that we got some cool scenes of Feral on his own hunting stuff (the wolf scene was great) I just felt like it would have made that moment feel a bit more "earned" if we'd cut away at some point to some sort of encounter between some of those trappers and Feral (maybe they arrive just in time to see him hanging some of their skinned buddies up from a tree and see him leaping away, etc.), rather than feeling like them knowing all about him came out of nowhere.
I imagine it's mostly because they didn't want the trappers to be properly revealed until Naru is captured by them, but it definitely made that part feel a little "off" to me.