The servers are inconsistent. The game will say you have 30ms of latency, and then you hit a back tap on an enemy with no shield, get the animation and the sound, without them dying. Very annoying.
This is a huge part of why Infinite weapon play feels inconsistent, it's very dependent upon networking connectivity. I doubt there is many hitscan style weapons in Infinite similar to the old Halo 2 era that "just work". It feels like a ton of smoke and mirrors in this game so you're really not seeing the "server authoritative" events play out in terms of movement, shots registration and more. I think this leads to conflation of aiming issues, it's compounded by the presentation layer in game of the networking behind the weapons and registrations.