Summary

If you add a task to a user on a page that have special characters (!@#$%)¨and then try to reach that page trough the tasks page, you will get a page not found error:

Steps to Reproduce

1. Create a page with the following title "Test!@#"
2. Add a task to your user on this newly created page.
3. Navigate to your task list page:

   BASE_URL/plugins/inlinetasks/mytasks.action
   

4. Now click into the hyperlink to the "Test!@#" under the Task appears on column.

Expected Results

You should be redirected to the page.

Actual Results

You get a page not found error:

Work Around

Just remove the "?focusedTaskId=2" of the end of the URL and you will be redirected to the page without problems.
The complete URL in my test would be BASE_URL/pages/viewpage.action?pageId=360457?focusedTaskId=2

Environment

Windows Server 2008 R2
MS SQL Server 2014