legacy USB audio device: malfunction through TB16, OK when connected to P 5530

Not so long ago I have reinstalled Windows 11 from scratch on my Precision 5530 laptop, connected to a TB16 dock.

I have several legacy audio devices connected, and working OK.

Among them, and "old" NAD Hi-Fi amplifier with USB 2 connection (with a late Windows 10 driver as recommended by NAD, no specific Win11 driver being developed).

The amp works beautifully when connected to one of the laptop's USB ports, but when connected to the TB-16 USB 2 port on the back or SS USB on the front, sound is stuttering. The TB-16 and all other devices connected to it work just fine.

Any clue to t'shoot that ? I have already removed & reinstalled the driver -> no improvement

If there was a conflict with another driver on the system (ASIO,...), the symptoms would be identical regardless of the USB port used, right ?