Why does back button in journey task page not work as expected?

Summary

According to the document referenced below - when user has access to the journey, then after navigating to journey task page from a link in the task notification, and then clicking the back button on journey task page header, he should be taken to assigned journey page.

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When the user clicks a link in the task notification, they are redirected to the journey task page. The user can navigate to the specific task directly from the task notification, such as Email, Bell, Things to Finish, and BPM Worklist.

However, they can navigate back to the assigned journey page to view all tasks