macOS Tahoe 26.5.2 and Neumann MT 48 issue

OK, so what has happened is that macOS update messed with your Neuman MT 48…

That is a known issue.

macOS Tahoe 26.5 introduced intermittent audio glitches (clicks/pops) and connection issues with the Neumann MT 48.

To fix this, you need to install the updated Neumann MT 48 Toolkit 2.0, and update your hardware firmware to v2.0

I also advise you to resist the urge to constantly update stuff. Updates can cause a lot of pain → [blog] Be careful with updates