A bug in After Effects with importing ProRes 4444 files with alpha
After Effects is not correctly interpreting the alpha Chanel of ProRes 4444 files - if there is an alpha fade in the imported 4444 video, a black shadow can be seen under the fade - this is the same whether premultiplied is selected or not. I have loaded the same files into Motion and Millumin and they work correctly. See the attached still - the text should be fading from transparent to white but is showing as transparent black during the fade.
Can you please try this in the latest Beta build? I believe this issue is fixed already in Beta.