[Micah]

If you click on the unit details in the recruitment screen you'll notice that the Magister has no standard paths, just a 1? path. Most of the time what that means is there is a 100% chance of getting a pick out of a few different paths, but in this case it means you have a 50% chance to get E1, a 50% chance to get A1, and a 25% chance to get S1, all rolled INDEPENDENTLY of each other. So, you can get anywhere from 0-3 magic paths, with 1 being the most likely result. The standard research formula for a mage is (2 + paths + magic scale mod) so your Magisters with more than 1 path get extra RP, but the unlucky ones that have 0 paths can't research at all.

So no, not a bug, and you missed the detailed breakdown of their paths, which tells you that some don't have research ability, though it takes a bit of deduction to get there.