Probably not relevant since the event never ended up in my Google calendar. The Hotmail calendar is tied to the Win8/10 calendar. I don't use the calendar anyway. I just noticed the notification and investigated. I already looked for a "report spam/junk" option in the Hotmail calendar and found nothing.
I don't recall ever enabling such a thing. I don't use the Hotmail or Windows 10 calendars anyway. My guess: This probably happens when you enable Cortana and give it access to everything in your Microsoft account. I think Cortana is trying to be helpful.
I use Gmail for at least 10 years now. My Hotmail account is one of those that simply will not receive some important emails, like registration/activation emails. It still happens even when all junk mail filtering is disabled. Those missing messages don't go to Junk/Spam. They just never arrive at all. After tolerating that for many years (I had Hotmail before it was Microsoft), I finally just abandoned Hotmail and never looked back. Forwarding to Gmail helped with the transition. I never had the missing messages problem with Gmail. The way Gmail handles conversations and labels (instead of messages and folders) is vastly superior.
I've had the same hotmail account since 1998. I just use webmail though and don't use Windows so the account doesn't sync with anything.
