Maybe I describe different situation to OP.
PDF viewing and downloading in this browser is still dead.
Release notes from build about 5 days ago said it was fixed,
go to URL https://www.amxaudio.com/products/product/14-nickel-plated-right-angle-plug
Click supporting document link
this the page that opens, a blank page no PDF
and none of the below tool icons respond to clicking, they are dead too so cannot download the PDF
and even MORE unmacOS like, Option + Enter key command does not download the file from the URL bar…
you see cursor in url bar is supposed to download the file on Option + Enter
BUT, if Compatibility mode is enabled then the PDF is displayed and all the icons respond.
So maybe set a rule to auto enable compatibility mode on PDF pages?