Is my XIAO Expansion board defective? or repairable?

I was asked by SEEED to place this in the Forum!
I just received my XIAO BLE Sense and two XIAO Expansion boards. It appears that one XIAO Expansion board is not working. Here is how I came to that conclusion. I attached new assembled XIAO BLE Sense to Expansion board 02 and I could not attach to it via Computer USB port. Nothing happened.
I then attached the XIAO BLE Sense to Expansion board and was able to hear the common PC USB attachment sound. After pressing Reset 2x I was able to download the newest UF2 firmware. I then loaded a “blink” circuitpython and it blinked. See reference picture “Expansion board 01”. With the “Blink” loaded I attached it back on Expansion board 02 with LiPo battery and later a battery bank as seen in the “Expansion 02” picture. Neither worked. I then noticed that the BLE and Expansion board were getting extra warm and disconnected it right away.

Additional test run today (14 February 2022. Just the board alone (no XIAO Microcontroller at all), when a LiPo battery was attached the area under where the XIAO BLE or RP2040 would go immediately becomes very hot!

FYI, I’m seeing the same not working/heating issue with 2 of my expansion boards when attached via usb connector.

Seems the 3.3v line is being pulled down to .82v when the Xiao BLE is attached to the expansion board. It’s 3.2v when not. It was working just fine, then stopped working. It could be the pogo pins not making good/intermittent connection while power is applied is toasting the power regulator or some such.

A related post about two 3.3v regulators tied together. With my next expansion board, guess I’ll try what is suggested in the post and remove the Xiao, 3.3v pin from mating with the expansion board.

Per this post I cut a trace on the expansion board, I can now use the expansion board with JLink SWD (via Pogo pins). I did have to connect the Jlink 3.3v input directly to the Xiao 3.3 rather than along side the other SWD connections. I expect the other board functionality is lost though.