Movies with no art now showing poster for random movie in guide

I've got a weird issue with all my movies that don't have poster art -- but only when viewed from the guide in a virtual channel!

I have some videos I've imported as movies that I don't need art for so I leave them empty. Before, where the art would normally be, there was a blank purple rectangle with a text title on them. Now, when viewing them from the guide in a virtual channel, the art is showing up as the poster from a movie I recently recorded.

Again, this only happens when viewing movies from the guide grid and after selecting them from the grid. Viewing the same movie in a collection, for example, properly shows the blank rectangle with text.

This is only happening with movies. TV shows with no art show up in the guide as usual with blank rectangles.

I've tested this on my Apple TV, my Mac, and my iPhone. It also appears this way in the guide on the server web interface. I'm on the latest server beta, though I just updated that today to see if it would fix the issue -- it did not! Before today I was on a server beta from mid-November with the same issue.

Thanks for any help!