So it was my Teroclaw hatchling vs his crab, I am obviously a flyer and he is an aquatic.
There were no environmental effects going on, no debuffs/buffs of any kind. His crab was using 'surge' because it was going first against my flyer with its racial bonus active, but every one of the 'surges' was hitting as (strong). How in the hell can aquatic attacks hit as (strong) vs a flyer? It wasn't just a visual bug either because each surge was hitting for 400+ dmg.