My 8 Plus is working fine except for one odd thing. At night, I place it on a Samsung Qi charger pad. It recharges to full then you get the "charge complete" ding. Problem is, as it lies there on the pad it continues to periodically ding through the night. Almost as if the charge drops slightly then gets charged back to full again. When plugged in to charge it does not do this. Anyone else experiencing this? Is my phone possibly defective?