Address poisoning scam on Metamask is a new way devised means introduced by scammers to steal users funds by using same address characters as the sender in hope the sender will not double check the full address before send out fund to a scammer. Secure your funds always by making sure to double check address before sending fund to any address. [Source](https://metamask.zendesk.com/hc/en-us/articles/11967455819035-Address-poisoning-scams)