Everytime he repeats sharing he gets the same problem. His version is 2.4.3.
I have 2.4.3 as well, and use sharing regularly. I got to the 'balance' tab, tap 'receive', scroll down, tap 'share bitcoin address', select 'gmail', type my email address, and click the triangle icon in the top right to send the email. It has never sent me the wrong address.
Is it possible you're being scammed?
Either way, I can't imagine you are liable for anything. You sent coins to the address you were given.