I'd expect unit calendars to remain with the unit and with the building. However, I wouldn't be surprised but what there's some oddities that might take a developer to fix. I would strongly suggest everyone visiting your subscription page to reset the subscriptions for the new stake - especially those that only use LDS Tools and rarely visit the calendar page.
Have you searched the
Help Center? Try doing a Google search and adding "site:churchofjesuschrist.org/help" to the search criteria.
So we can better help you, please edit your
Profile to include your general location.