Picked up the Apple 29W USB-C charger and an Apple 2M USB-C to Lightning cable to take advantage of fast-charging on my iPhone 8+. Upon plugging it in - it chimes/vibrates and shows the charging animation. Then, it goes away/off for a second - before resuming charging for good. Is this an intended feature of fast-charging? Or is something wrong. I’ve tried restarting the iPhone, different charging outlets, etc. Thanks!