I can create google calendar entries fine, but when I get events from Google calendar the start and end date fields come back as a blank, ? or invalid date in the collection. The error thrown say "expected value to be a valid RFC 3339 'date-time' format. Any tips appreciated.
PowerApps doesn't recognize Google Calendar event start and end dates as date-times
It is an ISO standard. You need to format the date in the format below. You will need to show your flow and how it is configured so we can see what you've done: