The server is not seeing the correct walking animations on each of the clients and after doing some digging, we found that the Pawn->GetVelocity() function is returning something drastically smaller on the server than it is on the client, which is causing the blendspace to play the incorrect animation.
This is also happening on dedicated servers as well. Clients do not have the correct velocity of the others. It seems as if the velocity that the server has is incorrect and therefore is incorrectly replicated to the other clients. The acceleration numbers seem to be correct and the position of the clients are correctly getting replicated just fine. But the Velocity and Speed are totally off
This can be replicated in ShooterGame and the Third Person Project in 4.20 (not in 4.19)
To reproduce, add this to the DefaultGame.ini:
[/Script/Engine.GameNetworkManager]
MAXPOSITIONERRORSQUARED=1600
ClientAuthorativePosition=true
That should cause the bug to appear.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-64576 in the post.