[Bug?] Ashes to Ashes not affecting all enemies when used with Multistrike

Working on a debuff team, and put an artifact with Multistrike on a Wilffire Efreet. Ashes to Ashes reads “if that target already has burn, it afflicts all enemies with Burn for 5 turns.” The first strike applies a burn to the attacked creature, but the follow-up strike from Multistrike does not spread the burn - it only reapplies it to the attacked creature.

Multistrike attacks happen at the same exact time, so if the target isn’t already burned before the first attack, the trait won’t activate for any of the attacks.

I suspected that was the case, but wanted to make sure. Thanks Zack!