Missing buff from flask

first iam new here. So, hello all :slight_smile:

Iam the raidlead and guildmaster of my own raidguild. We raiding and iam deep into logs to check some issues or fails.

Today i noticed a …bug? or a missing knowledge by me.

Theres the log: https://www.warcraftlogs.com/reports/yGYcz9KhDMtdpfr7/#type=auras&source=2&fight=6

this user took a flask of intelligence. I know it, cause iam with him. And wowanalyzer (https://wowanalyzer.com/report/yGYcz9KhDMtdpfr7/6-Normal+Zul+-+Kill+(5:11)/2-Shilonia)
told the same.

Why theres no buff from Flask?

Hope you can help me!

sorry for my bad english, it isnt my native language.

Edit: i know its “LFR” but that shouldnt be the reason