floral ledge
Pain only knocks enemies back once.
Steps to reproduce are just placing him and letting him attack.
I dm'd @desert swan about this a couple days back as I was curious if Pain should be knocking back units more than once. They confirmed Pain should knockback an enemy 3 times before they're immune. After like half an hour of recording (as it never wanted to send the recording) I had to resort to imgur to get the file through. He knocks back enemies once, and then those same enemies will never get knocked back again. Hyper thought that maybe the knockback had a 10 second cooldown just like Pain's buff, but if that was the case, (in the video) when Pain loses his buff, the third attack would've knocked them back again.
https://imgur.com/a/sIu7YRw
I attached my F9 Console as well (sure hope this gets even a little attention, I had to grind to Elite just to report it. If Hyper ends up being wrong about Pain being able to knock back more than once, that's alright)
graceful fox
ember mulch
shy laurel
fossil sparrow
true sequoia
wide sigil