For anyone that has not played Halo 5 Forge that is primarily a M/K player, or those who do and have not been informed. There is a "fix" for the latency which effects the controls. At this time there has yet to be a patch from 343i fixing this issue. This video will help step you through the process that improves the controls. Yes it is unfortunate. I do recommend turning V-sync off as well. That should help.
Here is the tutorial video on what to do.
https://youtu.be/ye2TRtiYv6I
As soon as 343i announces a patch for this I will make sure to update!