I only have one example of this, https://www.fflogs.com/reports/bBPpNVFZG4hqHAja#type=summary&hostility=1&source=126&fight=14&start=8983053&end=8997162&view=events
But I’m assuming this happens any time an enemy gains a buff from “Environment”. In this case, Brute Justice gained two stacks of Damage Up buff when two players died during an intermission phase. This buff effect does not show in the Buff tab, but shows in the Debuff tab instead.