I mean, I guess the guy was lagging since DS3 often has extreme cases of phantom range if your opponent is lagging, but I entered the swamp at SL25 and a guy with full hazel armor and this invaded me and killed me.
It was kinda annoying since for some reason my sunbro couldn't attack him/damage him and he seemed to have way higher stats as he took hardly no damage from my attacks compared to him nearly instantly killing me.
This has nothing to do with this weapon other than that he used it.
Any weapon has phantom range when the guy's lagging and it's stupid to see him swinging him over there and get hit while standing meters away.
But welp. Also I just hate people who don't upgrade to invade low level players. Come on.