How do you define coincidence? I do not define it as happenstance. I like this definition from the 1968 edition of the Webster Universal Dictionary:

“Noteworthy event, circumstance, or series of such, which occurs in conjunction, or synchronously, with others, and is of such a character as to suggest a connection of cause and effect, although apparently no connection of the kind exists.”

I recognize that's Jungian but in much clearer language.