I opened up a trade with ramses and he had archery but wanted to trade for hunting
This is on Monarch so I know that civs start with archers+scouts so i would assume that they start with Hunting as well as archery
I run the BUG mod but I doubt that that's the issue
SS:
http://i16.tinypic.com/7278n54.jpg

what makes you assume they how to hunt - just because they know arrows no one says they know how to use them ;)
that is the way it works since Vanilla was released - the AI gets Archery on the higher levels but not its prerequisite hunting if it does not have it anyway...
It is a tad inconsistent but I would not call it a bug - this just means that even on higher levels not all AIs can build scouts from the get go :)

That's really only Monarch. On Emperor+, they also get Hunting for free.

Bh