Newlines in strings are being replaced by //

Hi there,

This feels like a bug. I have a workflow that sends email for reset password requests and console invitation emails. These emails are HTML formatted. Everything was working fine yesterday (31/08) (AEST) and suddenly, a couple of tests today resulted in this hideous email:

Yes, I can use replaceAll('\/\/', '') before I pass this to my gmail send email endpoint but posting this because I'm mostly annoyed that I got blindsided by this. We're supposed to present this functionality on Monday to our client. Also, wouldn't this be considered a bug as this was working fine yesterday and I didn't change anything on the string containing this HTML. For reference, here's how the email should look like: