Topic: Fireface UFXII with another class compliant interface wont work

I know the subject title is rather vague, but if I named my other interface I didnt figure anyone would know what it was..

So, I have a M1 Mac Studio, Fireface UFXII, and just picked up a EFNote 7x for recording drums in my new less-than-ideal studio space...

The EFNote kit has a drum module with a built-in 8O-ut/2-In audio interface.
It's class compliant for the MAC I guess, as there is no driver available for it.
I plug it in and My M1 Mac sees it just fine.
However, recording audio thru it doesn't work when the Fireface UFX is plugged in.
If I turn the UFX off, the EFNOte works fine.
If I turn the UFX II ON, the Mac will either slow to a crawl and become very sluggish, or, best case scenario.. it will record audio in and the audio will distort horribly or speed up and slow down. Sometimes the daw will throw an error about sample rates changing.. typically showing 1/2 the sample rate I selected.

So yeah, it seems like a clocking issue to me.

I have tried Studio One, Cubase and Logic and the issue is present with all of the daws in one way or another.
Studio One is the worst offender, but they are all pretty unusable when both interfaces are plugged in.
Right now the only "working" work-flow is:

Power off the UFX
Start the Daw
Select the EFNOte interface
Change all the I/O to the EFNote
record my drums
then when I want to listen back on anything other than the headphones attached to the drum kit I need to..
Exit the daw
power on the UFX II
Open the daw
select the UFX II
reconfigure the IO for that interface
listen back

not a fun workflow.

Sorry for the long-winded post.
I doubt anyone else is running the exact same rig as me, but has anyone else dealt with issues using other class-compliant interfaces alongside the UFX?

Re: Fireface UFXII with another class compliant interface wont work

Using two different audio interfaces at the same time on one computer can be a bit risky sometimes. Anyway normally it’s not a problem having them simply plugged to the computer but only one of them is selected in one software as audio hardware.
Only to be sure: you don’t have created an aggregate device in macOS Audio-midi-Setup app, have you?
What device is selected as system audio hardware?
Is there any direct connection between the two devices (word clock, ADAT…)?

FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2