I ran Solo Ops GM K1 Logistics with Ashes to Assets today and the final boss applied scorch with his Solar Projectiles. But even when i ran out of his range the 45 Scorch stacks on me would only decrease to be reaplied by themself. Which kept me 1 HP forever and i couldn't do anything about it. They only decreased correctly after the boss died (after it killed me twice due to permaburn and igniting). So never ever use that modifier...