The work-around: after forcing AU examination, I clicked 'cancel' instead of 'OK', so that DP did NOT immediately re-launch the MOTU Audio System. Quit and re-launch DP, and the Wurly appeared in the Instrument Track menu as expected.
I updated Wurly V and SEM-V yesterday via the new ASC. Subsequently, Digital Performer crashed on launch. After restarting my Mac Pro, DP launched, successfully but Wurly V and SEM V were missing from the menu Project > Add Track > Instrument Track > Arturia.
In DP Preferences > General > Audio Plugins, Wurly V and SEM V are listed as having failed AU examination. However, during the initial relaunch after installation , DP had said all AUs passed examination.
I forced DP to re-examine via the Audio Plugins Preferences window. Both passed examination. However, when I restart the MOTU Audio System, the whole DP application crashes.
All software is up to date as of this writing.
Support request submitted to Arturia.
2009 Mac Pro 8-core 2.26 GHz, 16 GB RAM