First page of PDFs not displaying in Universal Viewer

We’re finding that the first page of PDFs don’t display in Universal Viewer. Any idea why this may be so?

Thanks.

This is very strange, since the pdf viewer included inside Universal Viewer is the pdf.js created by mozilla and used nearly everywhere on the web. I just updated the module to be able to use js library UniversalViewer (that the module integrates) v2 or v3. The issue is the same for v2?