I'm having lag issues about every other match. Random lag spikes where all I see is people running into walls or my respawn timer gets stuck at #. I have Time Warner Cable, 37 download, 6 upload. No connectivity issues or problems with other games just Halo 5. I know for a fact others are having this issue, as I've discussed it on the Halo 5 forums and on reddit on the Xbox One subreddit.
Here is a link to that discussion to add to the reddit post you've already referenced.
https://www.reddit.com/r/xboxone/comments/3qdwxa/halo_5_lag_issues/