Blackrock laggy movement with low latency

Hello,

I have been experiencing laggy movement as seen in the video below, even with latencies around 20ms. My internet connection was stable and i did not measure any packet loss at the time of recording. I have also seen other people complain about it as it leaves side effects such as people sliding while stunned or casts showing up late. I looked at recent posts and did not see any complaints about this and was wondering if this issue had been brought to light yet.

https://youtube.com/watch?v=hoB7gg7f0-c

Same is happening to me in arenas when I'm facing blackrock people, even tho I'm on Lordaeron. It's literarly unplayable, people are shoting through pillars, warriors are bladestorming and I can't catch people. Hope someone will find out what's up with that.