When the NoMachine session is connected from IGEL OS 11 (the OS version at the time this Trouble Report was opened is 11.03.500), USB devices connected to the thin client are properly listed in the USB device panel. However, once the device is connected inside the session, it's suddenly disconnected in 15-30 seconds. This happens at every attempt to connect the device.
No workaround is available.
This problem is fixed by IGEL's OS Release 11.04.100: https://kb.igel.com/igelos-11.03.100/en/notes-for-release-11-04-100-32873854.html