Hello, I built and downloaded the firmware to my desktop, and try to run flash_windows.bat script. But the script kept generating a new .bin file at the same folder, then I got the following output error.
Error during Upload: retrieving build artifacts: autodetect build artifact: multiple build artifacts found: ‘.ino.bin’ and ‘firmware.ino.bin’
PS: A same .bin file will be generated when upload the arduino-nano-33-ble-sense.bin, and everything runs well without error.
@KXCY Hmm apparently they put another Arduino CLI firmware out again apparently, and broke the way uploading works. We’ll take a look at it!
Quick workaround: rename firmware.ino.bin to firmware.bin or downgrade Arduino CLI to 0.11.
Great, it works after rename the firmware.ino.bin to firmware.bin; thanks. 
This has now also been fixed on production, new deployments will have a corrected script which works with Arduino CLI 0.13. Thanks for reporting @KXCY!