Difficulty with ProjectileMovementComponent

I’m having some issues with the ProjectileMovementComponent. The trouble is that the motion is falling out of sync between the client and the server. What’s happening is that I have an object being tossed by the player. This works fine until the server tells the object to stop moving or change direction. The object responds on the server, but the client sees the object drifting around randomly in the game level. The bReplicateMovement flag is set to true, but it doesn’t seem to have any effect. Attempts to manually replicate the position of the object to the client just causes a lot of stuttering as the client copy of the MovementComponent fights with the manually replicated position. How do I fix this? I need the ProjectileMovementComponent to handle the motion (gravity / collision / bouncing). But the server needs to be able to supply input to the motion now and then. How do I fix this? (This is done in C++ code.)