In halo 5 when i start a matchmaking game, the first minutes of the game feel really fluent and theres nothing i could complain about. But when I am in mid game the aim starts to feels very slobby and it is almost impossible to hit anything. I experienced these issues especially on forge maps. I am a very good halo player and i also play on a brand new gaming monitor from benq wich people use in championships so it is not the problem. It just does not make sense to me at all why this happens, I can not be the only one. Even after the update where 343 said they improved the aim it is still the same. Why can’t they just make it like it was in the beta?? I do not know how to fully describe it. It feels like suddenly out of nowhere i get input lag on certain maps.
Same for me. I can’t even play this game anymore!
Have you found any solution yet?? I really like the game and its really frustrating that i can not play to the best of my abillity 
The solution is to recalibrate your settings. Make adjustments until it feels right again. Not sure why it changes, but it does seem to.
What settings?? Are you thinking about the video settings??