I don’t have problems importing PDFs but I notice the corkboard view shows them either as text elements from the first page or the raw binary header.
iPadOS/MacOS have PDFThumbnailView, a class for retrieving a thumbnail from a PDF but it appears Windows doesn’t have something native for that (there are numerous libraries on Github but I don’t know how many are MIT licensed or in a suitable framework). If there’s something obvious I’m overlooking, my apologies in advance. Again, if I select either of these files from the sidebar they appear correctly in the main window, this is just about corkboard preview.
