5c Won't Charge if battery completely dies

Hi, so I've been repairing phones for a few years and have never come across this problem. When this iPhone 5c dies, it will only charge if you hold the power button and the needs charging logo comes up. If the phone is completely off it won't start charging. It charges perfectly fine if the phone is on, but if the battery doesn't have enough power to light up the charging logo when it dies it won't charge at all. I've tried different batteries, charging ports, and pretty much everything else. The phone doesn't have any problems other than this one, anyone have any idea what's going on? It's as if the phone needs a kickstart to get it charging.