ah ok, this is how it looks in my windows build. So thought it is by purpose a part of the map or so^^
I'm also new in Godot, so not sure, but based on Unity experience, i could imagine, that it's maybe something with materials or material variants or that you use accidentally something like a RenderTexture which shows the camera's viewport or so... (if these concepts are available in Godot at all^^) ... or because you say, there should be a health bar, also maybe should be a "world-scale" UI instead of an 2D/sprite element or so.?.. just random guesses, maybe something helps.
For the car: Damn, good luck with the new one :-)
