I had a similar problem with drop-downs being transparent.
By default drop-down are assigned FIELD, but none of those settings seem to affect changes.
A lovely support person sorted the flex alchemy. We updated the formatting of ALTERNATE PARAGRAPH either of the section's custom settings or in the theme seems to be the right object to change the formatting. In my case changing the background from transparent to white.
Maybe a change there will do the same trick, like the font color is white and needs to be black.
------------------------------
Sean Daniel
Member Services Manager
Telecom Council (Previously - Kerton Group)United States
------------------------------