Ok. create the problem. attach flightassist to avatar. like zed. or mystitools any flightassist allowing you fly fast.
Press page up. To fly straight up. at same time hold arrow down pressed to fly backwards n.up and same time. Hence fly diagonal.up.
You will see what i mean.
Goes same with any combination up or down in combo with forward or backward.
If you only use forward or back. so. Straight horizontal. no problems
Only up or down. So straight vertical. no problems. but diagonal. up n forward. or up n backward. down n forward. Etc. you will notice what im talking about.
No matter what gamehud u wear the problem is persistent and occurs with every player no matter what connection ping. Good or bad.
This is not an lag issue.
Diagonal confuses slserver or viewer ever since that server update. Prob pathfinder