Already posted about it elementalist thread but I doubt it'll get traction there:
I'm aware that persisting flames should not extend the fire field from overload as it isn't a weapon field, however should it not at least be proc by the field left behind? Conjured axe field (skill 4) does proc the trait, and yet it is technically a conjured weapon skill.
Maintaining the persisting flame buff is trouble enough already, this seems like an unintentional nerf to a trait meant to allow our flame attunement to persist.
Also, Lava Skin has been reported to proc the trait as well, even though it is not a fire field.