Lumia 920 Wireless charging quit

My 920 no longer charges wirelessly. I have both the charging pad and the charging stand. All worked fine for a while. Now, if I put the phone on either charger, I hear the ding, the plug icon blinks over the battery indicator, all looks good but the battery power keeps draining. The phone charges fine when physically plugged in, but wireless charging was a big selling point of the 920. AT&T is sending a replacement phone. I'm just wondering if anyone else experienced this issue.