Audio Unit v3 plugins work in Logic Pro never invoked in Audition

I am the author of a number of Audio Unit effect plugins, which I intend to release this year;  I've also been an Audition user for decades, back to being a beta tester for CoolEdit in the 90s.

The plugins I have written work fine in Logic Pro and Garage Band.  In Audition, they appear in the plugins menu, but when the menu item is selected, Audition never attempts to open or run them.  In Console, nothing is logged mentioning the plugin, nor does any logging the plugin would emit appear - it appears the plugin is simply not loaded at all.

Audio Unit v2 plugins work as expected, but v3 do not.  My best guess is that Audition sees them in the system's registry of audio plugins, but does not actually know how to load them.

The behavior is reproducible 100% of the time with this open-source Audio Unit v3 plugin on Github:

https://github.com/GeorgeMcMullen/AudioUnitV3Example

Are these just not supported?  If so, will they be?  Or is there some alternate mechanism available to get Audition to load them correctly?