Never seen this either. But I have seen a Fuling village next to a Swamp that is pretty much are the same as yours.

The craziest one I took down tonight and it took 2 ingame days to take down.
The village was next to the Black forest and had 4 Beserkers 3 Shamans and loaded with ordinary Fulings.

Of the 4 Bereserkers one was a 2 star, one was a 1 star and 2 was ordinary. Very rare to see a 2 star when playing solo and it was crazy strong. No I did not melee him as i would have been so dead if I had done that. :)