PDF links not loading in browser suddenly - have to be downloaded

It's a common practice for our Eloqua users to hyperlink to PDFs in our emails that are hosted in Eloqua. Typically, when someone then clicks the link in the email, it opens the PDF in the browser. Starting yesterday afternoon, when someone presses the link, it now forces them to download the PDF before it'll load in the browser. Support is saying it has to do with our UTM parameters? We haven't touched our parameters or any settings, so curious of anyone has any insight? Also, want to note that this isn't happening in landing page links, only emails. Thanks