Pages in a PDF being dropped with just an error-log message

Trying to excatly pages from PDF documents like this

PDDocument doc = PDDocument.load(new ByteArrayInputStream(pdf));
List allPages = doc.getDocumentCatalog().getAllPages();

But not all pages get read, and the only indication something is wrong is this error-logging:

ERROR org.apache.pdfbox.pdmodel.PDPageNode.getAllKids()#202: No Kids found in getAllKids(). Probably a malformed pdf.

I'm getting one of these error-lines for each page that isn't read. I'm attaching two different files with this problem. One gives me 4 out of 6 pages, and the other gives me none of the 4 pages. Both documents read fine in Acrobat Reader and in Okular where all the pages get shown.