Installed App from TestFlight crashes due to alleged UISearchDisplayController

I implemented Dark Mode with the current beta version of Xcode in a relatively old app. I uploaded these to TestFlight for my testers. However, this crashes immediately for anyone who has the public beta of iOS 13.

I've integrated Crashlytics into the app, and the cause of these crashes is as follows:

UISearchDisplayController is no longer supported when using this version of iOS. Please migrate your application to UISearchController.

All UISearchDisplayController instances have already been replaced by the UISearchController. The app doesn't use the UISearchDisplayController anymore. There is no longer any links to the UISearchDisplayController. Nevertheless, these crashes continue to occur, but only from the installations of TestFlight.

If the app is installed directly with Xcode as a "Debug" or "Release" on an iPhone with the public beta, the crash does not occur.

Does anyone have a solution for this problem?

After receiving the same error and finding no references to UISearchDisplayController across our app, we realized we needed to search for and replace searchDisplayController from within one of our storyboards. That corrected the issue after resubmitting a beta to TestFlight.