Hi thank you for your report and sorry for the lack of follow up. There are no robots writing on this forum, simply an understaffed team!
Adding calendars to a team is definitely something we could improve on. The confusion comes from the fact that you cannot currently create a calendar in a team. You have to create for yourself first, then share it with the team with edit rights. I also end up deleting the calendar from my own list then in such cases.
This is far from an optimal process to simply add a calendar to a team so we will look to correct this at the earliest opportunity.