Search function not working in PDFs opened in Safari

I do the following steps:

1. Open a pdf in Safari by clicking a link (like this one), which opens the pdf in a new tab
2. Press shortcut command + f
3. Type the keyword I'm trying to find in the pdf (e.g. "Staatsanwalt")
4. The tab freezes and I need to reload the page

It's an incredibly annoying bug, given that my current work heavily relies on this functionality. So any help would be much appreciated.