The battery, when plugged into the MacBook through a usb-c usb-c cable, blinks all LEDs at the same time, and does not charge.
When the battery is plugged into the same MacBook though a usb-c to usb-a adaptor, then through the usb-a to usb-c cable into the battery, it recharges. Only the top LED blinks until battery is full.
When the battery is plugged into a wall charger (either usb-c or usb-a) it charges normally as well. Very fast using the MacBook power brick with usb-c.
There must be a form of usb-c communication between the MacBook and the battery that messes with the charging. I am guessing it has to do with usb-pd (Power Delivery).
I tried all sorts of usb-c cables (100W, 3.1 v2...) but that does not make a difference.
System information on the Mac does not identify the battery on USB at all.
The Anafi battery will charge at 5V from a regular usb charger (limited through a usb-a port) but since the battery is 7.6V, I suspect it can trick the Mac into wanting to be charged. I wish there was a way to force a given usb-c port into delivering power only...
I can upload a video if anyone cares are has questions.