Audio MIDI Setup doesn't identify Focusrite Scarlett 18i20

I have two identical rigs, built at the same time using brand new equipment and identical software installations with the following specifications:

Mac Mini 2020 M1

OSX 12.2.1 (Monterey)

Focusrite Scarlett 18i20 3rd generation

Scarlett Firmware: 1644

Focusrite Control 3.7.4.1943

Interfaces are plugged directly into the USB-C port on the computers (no hub.)

On both computers, Apple System Report in About This Mac identifies the Scarlett 18i20 connected to the USB port, as expected.

Both rigs function perfectly, but there is a quirk in Audio MIDI Setup utility on one of them that is annoying and inconvenient.

On Computer #1, Audio MIDI Setup utility identifies the Scarlett 18i20 in both the Audio and MIDI windows, as expected.

On Computer #2 Audio MIDI Setup utility identifies Scarlett 18i20 in the Audio window, but in the MIDI window it shows up as USB MIDI Device. Rescan doesn’t fix it. The MIDI interface functions fine, but I need it to show up in MainStage and other DAWs as the Scarlett, not as a generic device, so I’ll have parity between the two rigs.

I’ve switched the interfaces, and this problem still shows up on Computer #2, so I the issue is with the computer or software, not the interface.

Fixes I’ve tried:

1. Trash audio preferences and and Audio MIDI Setup preferences, as recommended by the very helpful Focusrite tech support.

2. Installed Focusrite Control 3.9.0 beta, which works fine but doesn’t fix the issue. (The Focusrite tech said that this version, though not yet released seems to have solved several other issues.)

3. Booted in Recovery Mode and reset the NVRAM in Terminal with the NVRAM -c command. (As far as I can tell this is the closest thing on the M1 machines to the old command-option-P-R PRAM reset trick on older macs.)

4. Booted in Recovery mode and reinstalled the OS.