Have this issue too. Sumsung support tells me to exchange pad / buds. But pad is working and charging all devices excluding buds. Buds working too and charging by usb, and if case is not warm, charging by samsung duo is ok. But just it started to be warm by wireless charging, then charging is stop and start to discharging. A lot of users have this problem (reddit, this and other tech's forumes confirms it). Disappointed.
Huh, this is answer. Try to use onle left pad without any items on the right pad (When you use two pads all of them starting work like 7.5W charger).