MIDI keyboard not working on Mac Mini M4 front USB-C ports, but works on back ports — any ideas?

Hi everyone!

I recently bought a Mac Mini M4 (512GB SSD, 24GB RAM), and I'm having a strange issue with my M-Audio Keystation 32 MK3 MIDI keyboard.

The keyboard is not recognized when plugged into the front USB-C ports, no matter which USB-C to USB-A adapter I use. However, it works perfectly when I plug it into one of the rear Thunderbolt/USB-C ports.

What’s odd is:

• The same keyboard, with the same adapters, works fine on my MacBook Air M1
• Until yesterday, it also worked fine on the front ports of the Mac Mini
• Other devices work fine on the front ports
• The keyboard does receive power when connected to the front ports (the LED lights up), but macOS doesn’t seem to recognize it.

One of the adapters I use is from Anker, and I’ve tried a couple of others too with no luck.

Two extra details that might be relevant:

• I updated to macOS Sequoia 15.5 last night
• For now, I’m using a Ugreen KVM switch to share keyboard, mouse, and monitor between the Mac and my Windows PC, but I plan to finalize the setup soon

Any idea what might be causing this?

Thanks a lot in advance!