Safari update breaks embedded PDFs

Hi,

Embedded PDFs in a web system that we use at work has suddenly stopped working since the MacOS Tahoe upgrade. Works fine on Chrome.

iOS has the same issue. Worked fine until I literally just upgraded to iOS 18.7.1 and then Safari would load a white space where the embedded PDF should be.

There doesn't seem to be anything out of the ordinary in the html code - it's just an <object> tag to load in the PDF.

The only thing I can see that may potentially cause an issue (this is a guess) is that when I put the address of the PDF into my browser I can see that the address redirects to a different URL.

I wonder if this recent upgrade does not like embedding an object where the URL redirects?