HTC One e9+ : Once I turn off phone, red LED lights up and it shows as if it's about to charge?

A

AC Question

HTC One e9+ : Once I turn off phone, red LED lights up and it shows as if it's about to charge

Once I turn off phone, red LED lights up and it shows as if it's going to charge (battery image with charging mark inside it), this is accompanied by vibration as if I just plugged in the charger, then after a few seconds the LED goes off and screen goes black then the whole thing happens again (endless loop). This only happens whenever I turn off the phone and when not plugged in actually.
When i turn on the phone it's working fine.
It sounds complicated, but can anyone help me with this? '-'