One CPT doesn’t get correct editor colors

Hi, I’m having a really weird issue. My site has several custom post types, all of them created in the same way with the same settings. One of them however is acting up in the editor. I’m using dark theme support as the site has a black background. In that one cpt the color of the placeholder content is a very dark gray (probably the same one you get when not using dark theme support. This makes the placeholder text more or less impossible to read against the black background of the editor. Is this a known issue or is there anyway to change the placeholder text in the editor stylesheet using css?