This "Incoming Transaction" was sent to my personal email. It showed up with an official Blockchain.com logo on the document and came from an email address:
transaction@encripyted-blockchain.com. I don't have an account with Electrum. My account is with a different blockchain platform.
Thanks. So, 'Electrum accounts' aren't a thing, either. This is 1000% confirmed to just be a scam email; report it as spam and kill it with fire. Do not click any links and if you have, check that your machine is still fine.
Case closed.
The email address showing up on this "Incoming Transaction" is transaction@encrypted-blockchain.com. The bitcoin was being sent by Crypto Fund AG in Zug Switzerland.
Little addition: it is pretty easy to spoof your sender email. Even if it came from encrypted-blockchain [dot] com, that is some random domain someone registered which has nothing to do with blockchain.com. Lastly, blockchain.com has nothing to do with Electrum, anyway.
PSA: No legitimate (Lightning or not) wallet application notifies you about incoming transactions via Email.