the video I’ve uplouded to Ytb. maybe developers will debug clearly
this issue occured many times on a streamer I watched long time at douyin(tiktok)
I’ve never had this in 130 hours of play. 
try blocking Echo Knight’s attacking as many as you can, and not killing Echo Knight too soon.
This issue occured me sometimes. I don,t understand why stopped. Sorprised me.
maybe:
there is a movement link to control EchoKnight’s behavior and attack.
when the movements in link were consumed, and no new movement be added, this bug occured.
it,s posibble. Or Ecoknight go to start a new movement, but, for any reason, the movement dont execute.
Friend, I killed him 100 times, and the only glitches that I had, he fell off the horse immediately into the abyss and nothing happened, and it was that he got stuck on it in a rock, sometimes he even got out of it himself, but what you showed, this never happened 
who didn’t ? your samples are too few!