MacBook Pro 2017 Battery Strange Behaviour

My MacBook was running fine with 14 battery cycles, normal condition and 100% charge when it suddenly turned off. when i tried to switch it on it showed to connect charger. I connected charger and battery charge shoots to 100% in almost 3 minutes. System report is showing battery full charging capacity at 156 mah with 15 cycles and normal condition. but the strange is that battery drains in the same manner as is charged but at the down level of 4% it gave a download as well as playback of full screen movie of almost 100 minutes and no further drop in the battery percentage. can anyone guide me resolve this issue.