Automatic sign-color in cells

Hi to all of you,
since i installed version 24.2 (Win10) i have a problem in calc:
In cells with background color the color of the signs has changed from black to white.
In the cells which i have problems with the color of the marks is asigned “automatically”.

I have no idea how to fix this. Don’t like to change thousands of cells!?

thankful for any idea.