Hello, I work in position where I support a photographer, so let me lead off this post by saying that I have not experienced this problem myself.
The photographer is using Mac OS X 10.4.7 and PM 4.4.3.
Today, she said that she opened a contact sheet to view photos from a Lexar card. Then, she wanted to look at another card, so she closed the contact sheet and ejected the card. Then, she inserted a new card and opened a new contact sheet. The new contact sheet showed images from the first card mixed with images from the second card.
Is there some sort of cache function that's interfering here? I apologize for the secondhand nature of this account.
Thanks for any help you can offer.