Impulse Response Utility Not Recognizing Apollo Interface

I'm trying to create impulse responses with Logic's Impulse Response Utility app (IRU) and have run into a glitch.

I want to use my Universal Audio Apollo x8p Gen 2 interface to send the sweep signal to a power amp which feeds a guitar cabinet. However, when selecting "Universal Audio Thunderbolt" from the Audio Input and Output menus, the available microphone inputs and Sweep outputs aren't listing correctly. It only shows 4 possible inputs and 4 channels to output the signal to, none of which actually work.

After much troubleshooting, I discovered that when I have an IK Multimedia ToneX pedal plugged into my computer at the same time (which my computer and IRU identifies as a recording interface), that's when the IRU will not properly recognize my Apollo channels.

However, when I disconnect my ToneX pedals from my computer, the IRU does recognize my Apollo and works correctly!

The odd thing is, I discovered that it's only when I have more than one ToneX device plugged in at the same time that this issue occurs (which I normally do since I run stereo ToneX pedals). If I only have one ToneX pedal connected via USB, the IRU does still recognize my Apollo correctly.

So I'm not sure where the software glitch is occurring—with the Apollo, the ToneX, Impulse Response Utility, or somewhere in my Macs OS?