USB C devices are supposed to have resistors on the CC pins to help negotiate power delivery with the port supplying power and to allow detection of pin orientation[1]. But to save a few pennies (or because no one read the USB C specs), many cheap devices don't have these resistors and USB-C chargers that implement PD are almost certainly configured to not supply any voltage at the VBUS pins until a connection is actually detected. As a result these devices won't charge from a spec compliant USB C charger. Cheap chargers on the other hand may be nothing more than a basic 5V 1A USB A charger with a C port instead and happily supply power on the pins regardless of the CC pin status. Likewise A-to-C cables would do the same thing, since A chargers just supply 5V continuously without any negotiation.
Yeah, but some of these aren't "cheap" devices (Wahoo fitness devices have this flaw). Wahoo actually calls out Apple chargers in their doc, which is super annoying because it's NOT an Apple problem, it's shit design/penny-pinching from Wahoo.
And there are USB-C chargers (provided with Google phones and Belkin USB-C car chargers) that will charge the devices. So, I guess they're ignoring the lack of negotiation and just providing 5v? No idea.
So, consumers are left guessing what will work or won't. And carrying at least two chargers (one "dumb" and one "smart/PD").
[1]:https://ww1.microchip.com/downloads/en/AppNotes/00001914B.pd...