Vector images are imported as solid image
When you import vector images made in Illustrator, from the Library, they are imported as a "solid" image. So you have to "Import a copy" or open the file and copy/paste.
This is totally counter-intuitive and a waste of time.
When working with a vector document, you want the elements in vector, especially since this makes it impossible to send the file to an external service provider because the elements are not integrated in the document.
MBeuret shared this idea