I don't know if they are related, or how they could be. But yesterday I received four upvotes at the same time on unrelated questions. Later, around 1 a.m. this morning, my Gmail account that is attached to Stack Exchange was hacked.
Now I've received five upvotes at the same time about two hours ago.
The upvotes in themselves are suspicious, but combined with the access to the Gmail account I wanted to bring it to everyone's attention. I don't know if there's a correlation but the timing seems too coincidental to ignore.