Audio MIDI setup issues in Mojave

Hello, all ...

I'm experiencing some weird Audio MIDI Setup behavior on my Mac running 10.14.6. Devices already configured in AMS are being ignored and new ones are created in their place. For instance, I've a MOTU Micro Express USB, and it's connected to a few MIDI devices I have, both physically and in AMS. However, when I reboot, AMS will show the existing (configured) Micro Express as disabled, and show a new instance (Micro Express USB #2), which of course is not wired to my MIDI devices in AMS (the old Micro Express is). This is quite frustrating, as none of my MIDI devices work until I go back into AMS, rewire everything there, only to have it disabled the next time I restart.

Any suggestions on how to fix this (updating to Catalina is not an option for me) would be very much appreciated.

Regards,

John