Planner Tasks Due Date Inconsistent - Same Date, Different Day?

Question

Planner Tasks Due Date Inconsistent - Same Date, Different Day?

Brianna Hodge 20

The due date on my task seems to be inconsistent. If I select today's date it sometimes moves it to the tomorrow bucket and if I select yesterday's date it shows as late but in the today bucket.

Example - today's date is 31/08 but if the due date is set to 31/08 it shows as a task for tomorrow. If the due date is set to 30/08 it is marked late shows as a task for today.

It seems to only be happening with some tasks.

My Day View Due Date Column:

Screenshot 2026-08-31 093445

My Tasks View Sorted by Due Date:

Screenshot 2026-08-31 095007 Screenshot 2026-08-31 095507

I have tried changing my date/time zone to something else then back again. Anyone have any ideas?

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Answer 1

Allan Solomon Mejia 7,995

Hello @Brianna Hodge

This looks like a date/time-zone interpretation issue rather than the due date actually being changed.

Planner stores dueDateTime as an ISO 8601 timestamp in UTC, even though the UI presents it as a local date. This can explain why a task dated 31/08 appears under “Tomorrow,” while a 30/08 task is marked late but appears under “Today,” particularly if some tasks were created through different Planner/To Do clients, automation, or integrations.

Since it only affects some tasks, compare one affected and one unaffected task and check how they were created. If Power Automate, Graph API, Teams, or another integration created the affected tasks, inspect the underlying dueDateTime and its UTC conversion.

Also test the same tasks in Planner/To Do web versus the desktop/mobile client. If the actual due date is identical but only the Today/Tomorrow grouping differs, that points more toward a client-side grouping/time-zone issue than incorrect task data.

Microsoft documents that Planner due dates are stored in UTC:

Microsoft Graph – plannerTask resource

If you can confirm whether the affected tasks were created manually or through Power Automate/another integration, that would help narrow this down considerably.

Help make this community better for everyone: if this answer resolved your issue, please accept it or leave an upvote. If not, share more details in a comment so we can continue the discussion and find the right solution.

Brianna Hodge 20 Reputation points

2026-08-30T22:31:19.7966667+00:00

Hi, yes they were created via Power Automate. However some tasks generated at the same way are unaffected
Allan Solomon Mejia 7,995 Reputation points

2026-08-30T23:06:50.8366667+00:00

Thanks, that helps. Since the tasks are created through Power Automate, I would focus on the value being passed into Planner's Due Date Time field.

Even when the flow is identical, the source date can convert differently depending on whether it includes a time component/time-zone information. Planner ultimately stores dueDateTime in UTC, so a conversion around midnight can move the effective timestamp into the previous or next day.

I suggest comparing the Power Automate run history for one affected and one unaffected task. Check the exact dueDateTime sent to Planner, including the time and Z/UTC offset, not just the displayed date.

If necessary, normalize the date explicitly before Create a task, using Power Automate's convertTimeZone() or convertFromUtc() functions rather than relying on an implicit conversion.

Reference: Microsoft - Date and time functions in workflow expressions

Since some tasks from the same flow work correctly, comparing those two run outputs should be the quickest way to determine whether this is a Power Automate date conversion issue or a Planner UI grouping issue.

Help make this community better for everyone: if this answer resolved your issue, please accept it or leave an upvote. If not, share more details in a comment so we can continue the discussion and find the right solution.
Brianna Hodge 20 Reputation points

2026-09-07T00:03:44.9633333+00:00

Hi, been seeing how this works over the past couple of days and it seems to have fixed the issue! Thank you!