Shadow Mapping Issues
I am not sure if I have a similar issue to Shadows / Shading / Light Flickering + Texture Rendering (https://support.keenswh.com/spaceengineers/general/topic/major-bug-shadows-shading-lighting-flickering-texture-rendering) or if it is a new one, but I encountered some shadow-mapping issues in the fourth quadrant of the screen (bottom right of the crosshair), when I have my characters light enabled. There were no other light sources in the world which casts shadows (the interior lights which are usually put on the side of the starting lander have been grinded down, no other light has been installed yet) except the sun, which was on the other side of the planet, so there was only ambient light around, aside from the characters light.
It seemed to me, that it detected my characters light to shine from above on the object and therefore cast a shadow on the ground instead of from the front, where the character stands, which results in an higher z-buffer value than expected.
In Timestamp 0:16 you can see the refinery on the left with the wind turbine on the pillar next to it cast their shadows to the right bottom and the shadow is tilted as if the light was shining from above in a 70ish degree angle. So the light got an additional transformation in the shadow-mapping and somehow it was only shifted out to the fourth quadrant in the fragment shader.
When I wanted to recreate the error in a creative modless copy of the world with multiple light sources to test it out, it didnt occure again, not even back in the original single player world.
Maybe also worth noting is that prior to the appearance of this issue I had some strange FPS-drops on a flight down to 11fps or even 2-4 seconds long freezes in frames, the game engine seemed to run during that as all inputs during the freeze were computed. On later run tests to recreate the bug there were also no issues with FPS.