This is a regression from 4.19.2 (CL-4033788). The pawns aren't replicating their own movement on their clients, but they are replicating on the clients of other pawns.
This was reported and tested in 4.20.1 (CL-4233996) and tested in Main 4.21 (CL-4234136)
Results: The server copy of Pawn moves and replicates its movement to all clients and all copies of the Pawns, except for itself.
Expected: The server copy of Pawn must replicate the traffic to all clients and all copies of the Pawns.
Head over to the existingAnswerHub thread and let us know what's up.