Hi Walt,
I'm sorry I'm just seeing this now. There's a bug in the AU Component Registrar in Catalina which means that if you install and AU plug-in after you've launched Logic you'll need to reboot your machine after installing before Logic will see and scan it. There was and is a workaround in the installer that works for all MacOS versions except for Catalina. Again, I'm really sorry I didn't see this until now.
Dan
