I have been wireless charging my iPhoneX at night since I had it. It's been great. I had been on the iOS11 Betas but changed to iOS12 two nights ago and ever since when I put my phone on the stand, it keeps going on and off. As if I am lifting the phone on and off the stand. Every few seconds it does this. The screen lights up and it makes the usual sound but it doesn't charge. Is this an iOS12 issue?