Details and logs vast different

So firstly I am aware that there would be differences between the two, I but I am showing nearly a 4k difference which seems crazily high.

So this occurred on Heroic Conclave, I was tanking Pa’ku who we killed 3rd since pa’ku makes up 70% of my damage and he was healed to full twice I feel like logs aren’t accounting that damage which seems wrong. Wowanalyser also shows the same damage as Details.

Damage dealt to bosses that heal to full is irrelevant to killing the fight, so it’s not counted.