Internal error when using #f for application-preferences-handler

The docs for application-preferences-handler say that the contract for its handler-thunk argument is (or/c (-> any) #f), and that "if the handler is set to #f, the Preferences item is disabled."

However, installing #f as the preferences handler does not disable the system Preferences menu item, and clicking on it causes an exception when the library to attempts to apply #f as a procedure. (At least, this is what happens on Mac OS 10.14.6 with Racket CS 7.6.)

Note that you can't reproduce this issue within DrRacket, because DrRacket handles the system Preferences menu item. Furthermore, you will only see the error message if you start the GUI program from the command line: if, for example, you double-click on a launcher, thePreferences item appears to do nothing, and no error message is shown.

I've made a Gist with a minimal example program and a typescript (generated by script) showing the error message.

Start with the application-preferences-handler entry point and the minimal example program in the linked Gist, running it from the command line on macOS. Verify that installing #f disables the system Preferences item without raising an exception when clicked; use the accompanying script transcript to compare the current failure.