I got the Atom RS485 kit and my RS485 endpoint provides +12V DC on the orange header which I want to use to power the Atom.

I measure +13V at the DC12V input pin. Without the Atom Lite connected, I measure 4.84V at the 5V pin header on the base.

However, when I connect both, I cannot reach the Atom. Note that even with the Atom Lite in place, I still measure a fixed +13V at the DC12V input pin, hence I do not believe the source is unable to supply sufficient current (otherwise the voltage would drop).

However, if I power the Atom Lite via USB-C instead, everything works.

I thought already the base is broken, hence I ordered an additional base but unfortunately same.

Why does the Atom Lite fail to power from the 5V from the pin header?