Description.

When a blog post that contains a task with special characters or dates and was edited. Users will see a duplicate task created in the task view page. The issue does not affect when the task does not contain special characters.

Step to reproduce

1. Create a new blog post in any space.
2. In this blog post, assign a task which contains one or more special characters to a user, e.g.: [] @testuser: New task öäü!/();
3. Publish the blog post.
4. The new task should now show up in the user's task view (/plugins/inlinetasks/mytasks.action) only once.
5. Now edit the blog post by changing its page title, e.g. testblog01 -> testblog02
6. Save the blog post
7. There are now two or even more copies of the same task in the user's task view.
   For details, please review the following video
   Recording #53.mp4

Expected result
The task is not duplicated

Actual Result
Task is duplicated

Workaround
Admin can remove the duplicate task with the resolution provided in the following documentation.
https://confluence.atlassian.com/confkb/duplicate-tasks-appearing-in-my-tasks-or-task-reports-624525428.html