No joke, I have been receiving random emails with possibly privileged information from the largest corporation in my country for some 10 years now. It is as if Nokia started copying a random Finn to internal emails.
It is usually minor but relevant stuff - like invoices, B2B pricing, cargo reports, etc. Really boring. Probably a professional in the field could still make sense of it but for me it's gibberish.
Last year I got an invite for their Christmas party, with a request to select a menu option. That was nice of them.
So, yeah. These things happen. The ethical thing is to just delete the emails.