I generated a new BTC address (address A). I tried to send 0.003 BTC to address A. After sending them from my coinnomi wallet, the balance of address A remains 0 and from output seems that 0.003 BTC was send from address A to a mysterious address B. This action was not performed by me. Can somebody explain to my what happened. Thanks in advance for your time
https://www.blockchain.com/btc/address/1ECcv4vKES17iJFPVQ5Uoah5H5CzNJRXUo
EDIT: Problem solved. A good lesson learned. I used the mnemonic found on the code online without changing it. I am really angry with myself for being so stupid.
bip39.generateMnemonic
is trustworthy, I don't know what could've gone wrong. (BTW I'd call the function as bip39.generateMnemonic(256) to increase entropy to 32 bytes from 16)