Created attachment 200653 [details]
screen cap showing unexpected button colour on appearance change

When changing appearance via
Options | LibreOffice | Appearance
and clicking on the radio buttons system/light/dark to change between light and dark, then clicking apply, several buttons change background colour to reflect the new appearance but button text colour and the rest of the user interface remain unchanged.

For example, when changing from light to dark, upon mouseover the buttons at the bottom of the Options window become dark grey with black text while the rest of the dialogue remains light. If subsequently pressing okay to close the dialogue window , a new dialogue box opens prompting user to Restart Now or Restart Later, and these buttons are nearly impossible to read due to having black text on a dark background. The rest of the dialogue box remains unchanged.

If on the Options window you swap a few times between light and dark by pressing the radio buttons and clicking apply each time, you get to a stage where the Options window buttons do not change colour on mouseover, instead when clicking the light radio button the Apply and OK buttons instead immediately turn dark background.

The reverse happens as well leading to white text on a light background.