I have a few dozen of these email addresses and very rarely get spam to any of them - then received two spams to the same address within the span of a few days.

I have a few dozen of these email addresses and very rarely get spam to any of them - then received two spams to the same address within the span of a few days. It seems relatively unlikely that it was just guessing. I'll try to provide redacted headers within the next day or two so that interested parties can take a look anyway.