Opened a project created in CC2022 inside Premiere CC2023. When exporting through Media Encoder, I get a warning that "Color Matte" is offline. It's online in Premiere- everything looks fine- but then has a red offline image in the exported file. I tried making new color mattes inside CC2023 and replacing the existing ones throughout- didn't work. I tried creating a new project in CC2023, importing the previous project- didn't work. Tried clearing the Media Cache- didn't work.
p.s. i don't think the adobe website, and forums in particular, are easy to navigate, so don't spend a lot of time searching that forum list. do your best and we'll move the post if it helps you get responses.