Audacity 3.1.3 Dragging files to Alias in Dock stops opening files after initial launch of app

I have been using v 3.1.3 with High Sierra, and have used Audacity for years with other versions of OS X, never encountering this problem.

After upgrading to OS Catalina on iMac 21.5" i5 mid-2017, dragging a WAV or MP3 to the Audacity Alias on the Dock only works to open the files when launching the app. If I do some work and close the files I have worked on without Quitting the App, the Alias on the Dock no longer opens files I drag to it. This never happened before. Is this a bug?

This is a known problem and the developers are working on it.
– Bill