Did 10.13.x break external MIDI?

Folks -

I recently decommissioned my aging Mac Pro (well - retasked it), and replaced it with a Mac Mini I had from 2012. It's an I7 with 16G. Anyway, when I fired up the 'new' system in the studio, none of the external MIDI was working.

More specifically:

Roland/Edirol UM-880 (usb to 8x8 midi interface) - not working

Roland/Edirol UM-2 (usb to 2x2 midi interface) - not working

2 x Fireface 800 (RME) audio works but MIDI - not working

Now the interesting thing is that my Akai MPK-261 (controller keyboard -> USB) - works

Also, my Kurzweil PC3K7 works (synth -> USB)

The only thing I can come up with after scratching my head is that maybe the first 3 units are not CLASS COMPLIANT (they require drivers - which I have loaded). The two that are working appear to be CLASS COMPLIANT.

So - do I roll back to 10.12? Is anyone else having external MIDI difficulties?

Thanks folks!