Got a spam this evening offering PCB assembly services, to an address that's only used with Seeed, from a place called "BokTech".
Guessing Seeed had someone walk with their database.
The other possibility would be one of my orders got outsourced to them, and Seeed gave all the details but all my PCBs are either basic 1.6mm HASL or odd combinations that they don't do, so I doubt that.