Microsoft Teams

Hi kim_brown395,

you can try these steps:

Changing Due Dates:

• Microsoft Planner, integrated with Teams, lacks the ability to add due dates to individual checklist items within a task. While it's proficient for task management and team assignments, it lacks granularity for checklist items.
• A workaround involves creating separate tasks for each checklist item to set individual due dates, though this may not be optimal for large-scale projects.

Adding Due Dates to Planner Checklist in a Task - Microsoft Community

To try to resolve Adding Notes and Updating Checklist and adding Attachments, calendar Issues you can try to clear Microsoft Teams cache:

1. If Teams is still running, right-click the Teams icon on the taskbar, and then select Quit.

2. Open the Run dialog box by pressing the Windows logo key 

    

%appdata%\Microsoft\Teams

•  Delete all files and folders in the directory.

• Restart Teams.

New Teams

1. If Teams is still running, right-click the Teams icon on the taskbar, and then select Quit.

2. Open the Run dialog box by pressing the Windows logo key + R

3. In the Run dialog box, enter the following path, and then select OK.

%userprofile%\appdata\local\Packages\MSTeams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams

•  Delete all files and folders in the directory.

• Restart Teams.

 Clear Teams cache - Microsoft Teams | Microsoft Learn

If you are using classic Microsoft Teams, consider switching to the New Microsoft Teams.