UI Image dsiplayed as black when using Screen Space Overlay option


I am trying to create simple UI for my test project, but got into a display problem.
Simply creating a UI Image and applying a material onto it results in the attached result, in Scene it displays correctly, but in the Game mode it is simply black.

I was using 5.3.4 before, didn’t encounter this issue before. Yesterday i opened it on another machine with 5.3.5 (UI is created on both machiens from scratch) and have this problem now. Upgraded to 5.3.6 and still have the same problem.

I also asked some of my friends to open the scene and create UI, same problem. Now even if I create blank project i have this problem from the start.

I can switch it to “screen space camera”, but then i have lights influencing these materials, which, with some color grading results in washed out non-distinguishable textures.

Is there any settings I am missing or am i doing something wrong?

Would really appreciate any support