[Broken Isles] Combat Log Damage VS Actual Damage Dealt

[Nialsihg]

WoW Freakz link: -
Bug description: Mobs in the Broken Isles take more damage than what's shown in the Combat Log.
Proof: https://imgur.com/a/QREJXwz

Context: Back in 7.1.5 I made an addon that heavily rely on parsing the COMBAT_LOG_EVENT_UNFILTERED. With the 7.2.5 release I started noticing some weird behaviors and couldn't explain why. So I did some more digging and narrowed it down to this bug. I wrote a quick addon to better test this because at first I was running scripts from the chat and doing the math with a calculator.

Addon used in the screenshot: https://drive.google.com/open?id=1cUCoqZRj5i6Jz_SlcQ2vuNGPV7NAB5x7
Usage: /testdmg

Here is some other things I was able notice but would require some more testing:
* Mobs damage on players don't seem to be affected.
* Only happens in the Broken Isles.
* Not class related.
* Also affects pets.
* Doesn't affect auto-attacks.
* For a given mob, the damage multiplier varies with equipped gear.
* It appears in certain dungeons like EoA but not in others like CoEN.
* If it appears in a dungeon, it will appear in all difficulties (from normal to mythic+).
* Doesn't appear in raids.
* Within the same area, it can affect some mobs (Skittering Demon) but not others (Arachi Beast).

My guess is that we are doing the correct amount of damage but it's not properly reflected in the client.

[Barnacle]

This is probably to do with open world scaling, as you said yourself the damage done is probably correct but wrongly translated into the combat log.

XXX Barney