After fixed iPhone 7 audio IC, the phone won’t charge

Hi guys, I have an iPhone 7 here. It has classic audio IC problem: Grey-out speaker and takes ages to load. As usual I removed the big audio chip, did the jumpers, installed the IC, then I started to notice something is not right: the phone is warm and took ages to load, the system is very laggard, and the phone wouldn’t charge. I disconnected the charging flex from motherboard, then the phone was back to normal, the phone was quick to start and everything seems working properly with the charging flex disconnected. I tried two new charging flexes, same thing happened. As soon as I connected the charging flex, the phone was warm and slow to start.

Because the phone worked fine before I did the audio IC repair. I thought somewhere is shorted under the audio IC. So I removed the big audio chip, however the pads looked fine. Nothing is shorted under the chip. I installed the audio IC back to the board. Again same thing happened. The phone is warm and slow as soon as I connected the charging flex. The phone would work fine with charging flex disconnected.

I want to ask, does the audio IC has anything to do with the charging flex? I checked the components around the charging connector. They all look good. None of them was disturbed.

Thanks in advance for any suggestions.