Hi,
I recently got an Anker charger that supports QC 2.0 and 3.0 and for the first week it worked and it'd show "fast charging (x minutes remaining)" on the lock screen, however since a few weeks now it hasn't worked at home and across multiple countries. It simply shows charging while using the Anker charger and cable. I tried the same charger and cable with my friends Samsung phones and they Fast/QC.