Well at least I know I'm not alone. I figured I was the only person who ever used this controller ;-)

Hello DTS Engineer...are you still there? Have you looked at the simple project I created that recreates this issue?

I have uploaded a simple app that recreates the issue to Dropbox. Here is the link: https://www.dropbox.com/scl/fi/yb1b3zh3tzubx0oze6lc4/QLPreviewControllerTest2.zip?rlkey=3m9hiaw06550r5xs4xluoc5gz&st=i3x8obq0&dl=0 The app loads a ViewController with a single button that when pressed creates an object that generates and displays a CSV file via QLPreviewController. When the QLPreviewController is loaded the above flurry of warnings ensue.

I disabled SIP and installed the file and now i get the same issue as @kennywyland FileMerge doesn't show the error, but it crashes immediately with a crash report in Console.