Hi, I know this sounds like a very dumb/rookie question but I can't figure it out. I have comp A (imported from PS) that's a rectangle background with text & lines above it - which is inside comp B.
While on B I'm reducing the opacity of A from 100 to 0, normally over 10 frames, and the text and lines' opacity goes down normally... except the rectangle background! It's opacity is staying the same during the first 9 frames and then going from 100 to 0 in the last one.
As an experiment I replaced that PS layer with a solid from AE and it works fine. The whole comp's opacity reduced gradually from 100 to 0 over 10 frames.
What causes some layers to behave as described above?
There must be some kind of layer style or other thing going on with your Photoshop comp. We need to see a screenshot.
If all else fails, jut pre-compose the problem comp again and do not collapse transformations.
We need to see a screenshot with properties revealed for the problematic layer.