If you added layers to the Photoshop file, AE will not see them. You would have to re-import.
Once imported into AE you can't add layers, whether it's a Photoshop or Illustrator file.
That's correct to a point, however existing layers should update, and they are not.
try right clicking on a problem layer in the project window and selecting "reload footage"
Ok, so sometimes the 'reload footage' option was not available (greyed out), and using ctl+E>open in PS>save PS file, was not updating either. I"m importing the .psd files as comp/retain layer size or comp/comp, sequential import unchecked.
It's annoying enough, that AE won't see new layers. I wish there was better integration.
The only time consuming work around I've found is to re-import file and replace layers while deleting any duplicates....
Is this behavior still occurring? Please let us know.