anyone else notice earlygame figther jungles damage seemingly super high?

I'm starting to see junglers who are primarily fighters starting to do assasin level dps and it's usually in the early game when they have like 1 item and I cant figure out why. I've vs'd jarvan, panth, and jax most recently, they all used to be fighters with respectable sustained damage but now theyre doing like 60% of my adc's hp in under 2 seconds with like i said only like 1 jungle item and maybe boots and 0-1 kills. Anyone else notice this or can explain?