The more I think about it, the more I am frustrated by this. Runes either have a fixed tradition listed in their traits, or they can be any of the four traditions. Given how the magic traditions overlap, this feels pretty silly.
For example, Atryl, rune of fire, is a primal rune. Why can’t it be an arcane rune? Primal and arcane have equal access to the matter essence and fire spells, but I can’t etch an arcane fire rune?
The solution also seems pretty simple. Just put a “Traditions” entry at the top of each rune, right above the “Usage” entry. Frankly it’s probably easier to quickly read over than checking the traits of each rune anyway.