DA14683: Troubleshooting high current (3-6mA) during sleep

DA14683 Pre-emptive Links to documents:

Datasheet = https://www.renesas.com/tw/en/document/dst/da14683-datasheet?r=1600766

Hardware design guide = https://www.renesas.com/tw/en/document/apn/b-061-application-note-da1468x-application-hardware-design-guidelines?r=1600766

Platform Reference = https://www.renesas.com/tw/en/document/mas/um-b-044-da1468x-software-platform-reference?r=1600766

Software Dev Guide = www.renesas.com/.../um-b-056-da1468x-software-developers-guide

Hardware:

Custom DA14683 Board

Latest SDK = 1.0.14.1081 (last updated in 2018)

Situation:

Relevant Threads: 

1) "DA14683: Implementing a "soft power button". Push to sleep. Push again to wake." 

https://community.renesas.com/wireles-connectivity/f/bluetooth-low-energy/29023/da14683-implementing-a-soft-power-button-push-to-sleep-push-again-to-wake

2) "DA14683: How to troubleshoot what is blocking extended sleep modes?" 

https://community.renesas.com/wireles-connectivity/f/bluetooth-low-energy/28510/da14683-how-to-troubleshoot-what-is-blocking-extended-sleep-modes/100138#100138

3) DA14683: Can't sleep with debugger attached, where in the SDK does it abort?

https://community.renesas.com/wireles-connectivity/f/bluetooth-low-energy/28953/da14683-can-t-sleep-with-debugger-attached-where-in-the-sdk-does-it-abort

NOTE:  Before anyone starts asking if these issues are custom hardware related, I can run both the pxp_reporter and BMS demos on my custom hardware, and both sleep with currents in the 300uA range.  Given this information, if you still think this is still a hardware issue it would be helpful to maybe suggest some actual troubleshooting ideas instead of just saying "hardware issue".

To repeat my goal here, I'm trying to implement what is essentially a soft power button. Push to sleep.  Push again to wake and reset the system.  Because of this, I need to retain essentially nothing during sleep.  I should be able to shut down everything.  The only thing I really care about is being able to wake the system back up with the same button.  The system will fully reboot on wake up.

I think I have finally got the DA14683 into a condition where there are no more parts of the system blocking sleep.  I shut down everything I could find to shut down, and when I issue the "pm_set_sleep_mode(pm_mode_extended_sleep);" command it looks like it's actually doing it.  Nothing is blocking anymore.

That's great, but the sleep current is still in the 3-6mA range.  This is too high.  Occasionally, after about 45 seconds or so it will drop down to about 600uA.  This is still high, but barely acceptable.  Sometimes it never drops down and stays in the 3-6mA range.

Questions:

1) How can I troubleshoot what is pulling current while in sleep mode?