BBC SO Pro 1.2.1 - can't set default preset to "None"

As above. When I set it to "None" and click Save, then close and open the plug-in again it has defaulted back to Violin 1 Leader. Is this a known fault? I prefer to set all my Spitfire plug-ins up to default to "No Preset Selected" on opening.

The same thing is happening with Hammers, which always defaults back to Ensembles.

All the others, as far as I can tell, seem to be working as expected.

I've tried setting the BBC to default to something wacky, such as Percussion: Harp and this seems to work, it's just the "None" option which doesn't work.

Am on macOS Big Sur using Logic 10.6.3. This problem has come to light after a clean re-install of the OS and subsequent repair of all my libraries.