[Bug] SharePoint Online Calendar Sync with Outlook not syncing "Meetings" correctly.

I have the same issue but with a SharePoint 2019 on-premise calendar synced to Outlook 2016.
But the issue is more complex:
- when you add a meeting to Outlook, the item is not synced to SharePoint directly. When you press send/Receive, you get an error "Failed to copy one or more items because some are not compatible with SharePoint". But it shows up in the SharePoint calendar at that point.
- when you try to delete a meeting from the calendar via Outlook (right-click, delete), the meeting is opened and you can send the cancellation. But you get the message that changes cannot be saved to the meeting because it has been updated by someone else. After that, the meeting seems to have changed into a simple appointment where the attendee information is not there anymore. Opening the meeting and cancelling it (instead of deleting it) seems to work.