Apple - MacBook Pro USB-C adapter and regular USB devices compatibility

It looks like this particular product (uniHub-C) has its own idea about compliance to USB specifications. The designers seem to cut off the USB 2.0 part of the VIA hub design. First sign is that their marketing blurb doesn't mention support for legacy (HS, FS, LS) devices, which is strange - in marketing, more is merrier. Second, the web page shows some goofy "USB Super-fast" logo, which in no way corresponds to the official USB-IF certification logo,

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I suspect you fall for a wrong device.

I have the same problem with this hub:

Peripheral connection doesn't work (power, display and network do), and seems to be known issue (search for peripheral or Logitech) in the comments.

I connected another USB C hub in the other port in my Macbook and it indeed works.

Dongle hell.

Edit: from the comments in the link above and elsewhere I have read, some of these USB C Hubs have a problem with input devices connected at the same time (power + something else) from the same Thunderbolt port in the Macbook.

I have reached out to the manufacturer to see where the fault might lie, and if there is a mitigation. For now, using another hub without power/display in the other Thunderbolt port works.