The light wouldn't charge. No LEDs would light up, it was like I never connected it to power.
Eventually I tried another cable I had in a drawer and it worked. Then I found another one that works.
I have no explanation. From my point-of-view they are all USB-C cables. None of them have any indication of what's different between them. They all connect to the same plugs. They all look the same but behave completely differently.
I now know that I can't just carry 1 or 2 USB-C cables. I need to find out which ones work with which devices and keep track of that.