Just tested and got the same results. Single Player, multiplayer dedicated or not they do the same.
I have also been trying to get a weapon that gets attached to drop as well. The behavior is weird, If I detach it with the transform rules set to keep relative the weapon disappears. If I set it to keep world its like it stays attached and keeps moving with the player(not sure how to debug as I am relatively new to UE.)
I tried in a new project to test and see that it works, and it does just fine. I even set it up multiplayer some what and it works. Maybe it has to do with a blueprint project having code added to it, not sure if I am doing something that is causing it to not work. I’m going to try it in a code project and see if that helps.