Hm, I’m seeing same thing with shadows pausing after a bit. I’ll enter a bug report for that and see what developers say.
It looks like you’re setting this up in your Character Blueprint, so you can skip Casting step. In image above, you’re casting to yourself, which is unnecessary. Instead, just call Hidden in Game node directly off mesh you want to hide. If you only want to hide a certain portion of mesh, you’ll need to have mesh split into several components. If you look at FPS template, you can see how this is done: there is a mesh for full body and a separate mesh for just arms. There is also a checkbox in Rendering section of a mesh component’s details for Owner No See; this is how hiding mesh from player is handled in multiplayer games.
Is that what you’re attempting to do here? To switch from a third person to a first person perspective? I’m not exactly clear on what issue you’re running into when you press S, or how you have your camera set up.