This is an issue that's been present in Orion for quite a long time:

When loading any PDF from a link, Orion fails to load the PDF and just shows a blank viewport until the page is reloaded where it then displays the PDF.
Expected functionality: the PDF shows first try and doesn't show a blank viewport or require a reload to work.
Version 0.99.131-beta (WebKit 621.1.2.111.4)
Sequoia (15)