Text sharpness randomly fluctuating on buildings

I have three buildings upgrading next to each other.
The 0% that is visible on all three is sometimes completely white with blurry undefined edges.
At other times it is "sharp" with a black contour defining sharp edges.

Which has which is changing all the time without relogging, just by hovering with my mouse over them, or moving the screen to another sector and back.

Experiencing the same with hovering the mouse over buildings to read their name, or collectibles.
Sometimes well defined black border for the white text, sometimes border is missing and the text becomes blurry white.

Is it game-breaking? Not at all.
Does it make the game less visually pleasing? Yes.

Edit: UI is already set to 100% and automatic scaling has been disabled.