I don’t know how Electrum chose that wallet for sending the payment , is the choosing of the wallet automatic from Electrum ?
Maybe its a change address. You can read about change addresses in the below links:
What does change address mean inside Electrum wallet?
What all the addresses are in my Electrum wallet?
I am not sure why change address is starting with “3” which can be a p2sh-segwit address because input address bc1qxesjp5g4d23kpt9xghwxlu4mfhu9xxrehp0ytnm023ely43kdh9spsy4k7 is most likely an address from 2 of 3 multisig wallet with p2wsh addresses.
