High current draw on sleep [Board repair]

Hi there!

So I got an iPhone 6 that came in for BaseBand CPU reball (classic searching no service issue) and battery replacement since it had poor battery life. While I was troubleshooting and ruling out any bad antenna/housing problems I noticed that after the phone is booted and it goes to sleep (locked screen, or stand by, whatever you want to call it) my bench PS showed normal current (low, like 40mA) for two seconds and then went up to 200mA and stayed there. This is very noticeable with the battery since it depletes a full charge in about an hour or so of being asleep.

I decided to do the BB CPU reball with short jumpers hoping that some cracked ball or the phone trying really hard to get signal would solve the issue but it didn't.

Things I've tried:

-Restoring with itunes (clean, no backup)

-New battery (of course)

-Known good battery

No signs of heat or physical damage on the board.

Board looked pristine before I worked on it, and since I see it going down to normal current values I ruled out any full shorts (maybe a parcial short, or full short on some circuit that only activates while the phone goes to sleep)

I have not asked about fake charging cables, but I have not seen this sympthom being Tristar related before, but maybe I'll replace it just to rule it out.

I've never seen this before.

Any ideas will be highly appreciated!

Regards from Argentina, Rodrigo.