Coinbase selling email addresses (or another breach?)

I made a swap on some cryptocurrency that I had originally bought from Coinbase. Very shortly after I received an email, a scammer, asking me to confirm the transaction from Coinbase.
The funny thing is is the email that I use for Coinbase is unique and no one else has it. Also the transaction that I made was a swap between two wallets and unrelated to Coinbase….. So someone was sitting on the block chain and had my unique Coinbase email address somehow.

So the question is, does Coinbase sell our email addresses or is there another breach?