Diamond Flask Snapshotting Issues?

Whats the best way to look at Diamond Flask usage on a tank in a fight if they’re using the healing set snapshotting technique pre pull and entering the fight with a different trinket equipped? It seems like aura application isn’t being captured pre-pull, so the only way to tell if they’ve used a diamond flask is through healing ticks, is that correct? Is there another way to know they activated a diamond flask?