UMG Slider input doesn't work in multiplayer

I have a UMG menu for each character in my game and that menu has a slider component on it. It works fine in offline mode, but in multiplayer it is unreliable. The slider just snaps to 0 or 1 and can’t be moved. I’ve disconnected all logic from this slider to verify that it’s not my fault and the bug still occurs. From what I can tell it’s somewhat unpredictable; sometimes the client breaks, sometimes the server breaks. Sometimes the client breaks only after the server touches the slider, and vice versa.

I was actually experiencing a similar issue in editor. In my case, I had widget interactor components set up for each user’s pawn and a dedicated server hosting the space the users were in.
The solution for me was to remove the widget interactor components from every user’s pawn except the local user.
This means no widget interactor components on the server, and no widget interactor components on the simulated proxies. In a c++ environment the code looks like this: if (IsNetMode(NM_DedicatedServer) || (IsNetMode(NM_Client) && GetOwner()->Role != ROLE_AutonomousProxy)) { WidgetInteractor->DestroyComponent(); WidgetInteractor = nullptr; }
It unfortunately does not fix the bug in multiplayer in editor, as the editor can still see each local player’s widget interactor and will throw sliders to 0 at a whim. The only fix I can think of is to make sure only one widget interactor component exists in the whole of the editor during play, which may require a bit more of a hack.
I hope this is at least informational, even if not terribly helpful.
-Spiris