XPS 13 - 9380 need a factory reset to boot if powered off unplugged

Hello,

I need assistance or ideas from the community to help me to solved a complex issue with my XPS13.

To make it short, it's working well as long as I don't power-it off (sleep is ok). If powered off  I 'm only able to restart it with a factory reset every time.

This issue follows a replacement of the mother board.

Thanks for your help !

Long Wei

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The details

My hardware:
I own a this nice Dell XPS13 (developper edition, running linux debian) since 2019. It's the 16Go / with touchscreen, I love it and really want to continue to use it as long as possible.
Battery was replaced recently, power charger is new, cmos battery is new as well.

Motherboard replacement:
Early this year, the motherboard had a serious issue (some component burnt preventing a repair) and It took time to find a spare one in good condition as Dell isn't selling it new as spare anymore.

Last month it was finally repaired by a local shop, they are not expert in Dell hardware and I'm looking for more information in this community before sending back my laptop there (also  I can't currently work without my laptop).

The problem:
Back from the repair shop, after testing it with the repair team, the laptop was on sleep mode and I could restart it and use it without issues, until I powered it off.
Then, I could'nt power it on again, no power led when plugged, no light at all, no effect of the power button...
I had to do the factory reset procedure to start it again.

Details:
- Everything starts from a factory reset (unplug charger, disconnect battery, cmos battery, wait for 1 min, plug charger again, boot).
- XPS boots fine, I can go to BIOS, I can reboot when plugged and boot to debian OS

- then I can use the laptop with no issues, works plugged, and unplugged, all dell tests pass, the battery is discharging smoothly and charging smoothly.

Then comes the weird part - sleep mode OK, power off not OK

• It can go to sleep mode and restart without issues (plugged or not plugged)
• It can be powered off and restarted while being plugged (can restart after a long period if remain plugged).
• BUT if I power it off unplugged or if I remove the plug while being off after a power off, I cannot restart,
• The only way is to do again  need a CMOS reset (starting point).
• I don't think this is a linux kernel issue because this power off issue happens even if I am doing this from the UEFI BIOS interface without booting the OS
• Note: Service Tag of the mother board is not matching my original service tag and I cannot change it from the BIOS interface

Conclusion the laptop is usable if I don't power-it off, or if I reboot it only when plugged otherwise I need a torcs 3, the charger an access to a powerplug and a 2 minute procedure to reset it.

any idea ?