Vocalist and the Staff Text options - How to Use Staff Text options -Switching between available phonemes

Using an updated MUS4 with the latest Muses Sound - Choir

I've added the Staff text for Vocalist - Man and Women on first note in each measure and selected the option 'Ahh', 'Mmm' or 'Ohh' Sound. See the attachment.

The expected playback sounds would be a change on each measure to the selected option sounds. Unfortunately, this does not produce any audible sound changes from the original sounds of 'Ahh' for either the Men or Women vocals.

Is this the expected behavior?