Hi Rudy,
Thanks for getting back to me! Let me try and answer all of your questions.
- Yes, I just created a new project.
- Here are the steps I followed to reproduce it: First, new project from the First Person Shooter template. Then, make a UMG Widget blueprint, put some text or imagery on it. Then, take the base character and add a “Widget” (WidgetComponent) and set the Widget Class to the blueprint you just made. Make it a child of the camera (still working in the character’s viewport tab of their blueprint here, no blueprint graphs are involved.) Set it to Draw Size: 1920x1080, then scale it down in front of the player’s camera. Now it floats in front of the character.![alt text][1] Set to Screen so it doesn’t get affected by Motion Blur etc. Set to Only Owner See so others can’t see it. Then, Launch with a server and client (2 players in editor). Both players can see each other’s HUD rendering on their screen and position changes as they move about, even though I have Only Owner See on. This does NOT appear to happen if you render it in World space though. Attached two pictures showing both projects with the same result. In the new project, the other player is standing to the left of the viewpoint we see there.
- I have not encountered this issue elsewhere as of yet. This is specifically happening with the “WidgetComponent” you can attach to a character or other blueprint. Tooltip says “A 3D instance of a Widget Blueprint that can be interacted with in the world.” If you set it to Screen instead of World it doesn’t listen to the Owner Only See checkbox, or so it would seem.
- I have a screenshot of the actual result on my current project I encountered the issue on (hid some text, etc due to its proprietary nature) but there are no blueprint graphs specifically involved here. This is 100% done on the Widget settings in Viewport on the character blueprint.
edit: No clue how to use the image formatting on here. 
Links below