Are you able to see the cards with due dates on the Calendar in Trello directly? Is it possible that the "due dates" have been changed fairly recently? The update frequency is dependent on how often the app pings our server via the feed for updates. From experience we know, that most services or apps do this only once per day, so the changes may not have been requested by the Calendar app to be sync'ed over to the Calendar app.
You may also want to check out the Cronofy Power-Up which is a service that links calendar services like Trello and Outlook or Google Calendar, and updates much more frequently as it uses the API and is easier to set up, especially when using multiple boards: https://info.trello.com/power-ups/cronofy
Hello Community! My name is Brittany Joiner and I am a Trello enthusiast and Atlassian Community Leader. I'll be sharing with you a series of videos with my top tips on how to best use Trello...
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