I believe you are correct. The dragon’s AOE visuals don’t seem to match with the damage application. There seems to be several issues here that involve both the tailswipe AOE and the fire breath AOE.
Tailswipe AOE
This AOE is larger than the visual provided and can hit the player even if the tank is clearly standing outside of the visual. The AOE also extends to the front of the dragon, meaning tanks that are too close to the mouth of the dragon will take damage from the tailswipe AOE even if they are clearly standing outside of it from all other player perspectives.
Dragon Breath AOE
Like you described Burnator, the dragon’s AOE seems to turn with you if you dodge too fast. It also seems to apply before the visual goes away.
Its clear that the AOE visual warning is mismatched because the Dragon’s AOE breath animation occurs while the warning field is still up, yet it does no damage during the first second.
When dodging too fast, the dragon’s breath seems to follow the tank even if it stays stationary. The result is that the tank gets hit by the AOE even though they are clearly out of the AOE, and that the dragon hasn’t turned with the tank.
I hope these bugs can be addressed soon.
If you are referring to the Sentry boss in Tradu Labs, the laser beam attack still hits targets close to the boss behind him even though the AOE warning visual is nowhere close, another bug that hasn’t been fixed.