MacOSX: Cepstral interfering with built-in voices

[Anubis]

If I switch back to a built-in OSX 10.6.7 voice, like Alex, after a Cepstral 5.2.0 voice, like David, Alex's audio will be clipped and gurgled.

If I reopen the app, the voice is fine.

This is easily testable through "System Preferences" in the "Speech" panel where you pick voices from the "System Voice" popup menu and click "Play" to hear a sample.

No errors are logged to Console.

I see something similar listed in the 5.2.0 Read Me as a "Known Issue" but it says "under investigation" and dated May 25, 2010, more than one year ago.

Is there any progress?