Despite no longer consuming ignites Firestorm can not apply flammability or ignite.

Previously Firestorm was an ignite consuming payoff skill, it got reworked in 0.3.0 to remove any ignite interactions, and instead get benefits from infusions.

Before 0.3.0 Firestorm rightly could not apply ignite, because it was intended to consume them. This limitation is still in place even though the skill has been reworked.