Published calendar contains old events

I added an Apple calendar to my Google account, subscribing via a URL like below:

webcal://p50-caldav.icloud.com/published/2/MTEw...

The calendar shows up in Google as expected, however it's also showing old events that I deleted from iCloud long ago. I removed and re-added the calendar and they still show up. Any idea how to fix this?

Note, for clarification: these events are NOT in the (shared) icloud calendar. They are NOT in that Calendar on the Mac. They are NOT in a shared calendar a Mac. They ONLY come through the webcal URL.

This is happening iCloud (web) to Google, not in the app.