So, once again i'll post regarding this issue,
For all xbox players, whether or not you are on the origional xbox, xbox one, xbox one x or s.. Whenever playing Black ops 4 and somebody joins or leaves an xbox party chat you recieve a slight "lag" or "jolt" ingame when playing, I highlighted this issue with ATVIASSIST via twitter and they requested me to clear my cache and also to see my internet speeds.
I cleared my cache multiple times (lost game save data I didn't want to) and also posted them my flawless speed test results (wired). They forwarded my issue on in hopes of getting more information on the subject and this was their response...
"Hey, I just heard back. This is normal. Whenever a player joins or leaves a match or a party chat, the host system first has to send several game states to the new player (if someone joins) or receives repeated send failures and retries sending those game states to the player (if someone leaves). The host system then has to update all of the clients with the new game state. All of this takes place in less than a second (usually), but it can cause a slight hiccup for all of the players that remain in the match while it is happening. ^EX"
From what I take from this response is the following, - They think it's normal for this to occur when a player leaves / joins a party.
In my opinion this isn't normal at all. After going into previous Call of Duty titles and testing this I can assure you this is the first time this has happened in a call of duty title to myself. Playstation 4 dosen't get this issue at all.. which means it has to be something with the core code of the game on the xbox platform.
Furthermore, I'm pretty sure xbox live party chat servers are hosted on a completely different platform than Ingame servers. So why should we lag ingame when someone leaves our party.
https://www.youtube.com/watch?v=8qDsExUT18g This is the video In which I took showing the issue for anybody not understanding what I wrote. (Please skip to 26 seconds to see the lag when somebody leaves the party and continue watching to the end to see lag when he joins.
i watched your clip
and you are trying to show a hiccup and say it is lag. also custom games are not very good way of showing how an "in game issue" yes there is less than half a sec lag when your internet is doing multiple things at once
and clearing your cache doesnt delete game data. you would have to delete game data your self. if any game data was missing after a cache clear it is becasue said data was corrupted.
to help with the lag i would suggest to port forward your modem/router to allow the best connection with the least amount of interruption.