Multiple player FPS blueprint asynchronous projectile

Hi guys I just created a blueprint version FPS template to start build multiplayer FPS game, I found my projectile bullet has different hit judge on the edge of collision body.
if I hit exactly above another player’s head, my own client wont show hit effect but my other one shows it like the pic shows

https://forums.unrealengine.com/filedata/fetch?filedataid=156076&type=thumb

the replication I build for shooting follows a youtube tutorial, player run a server event first then run multicast event of fire. can anyone help me to point out what I did wrong?