'My Discussions' is not showing the correct count once a user unregisters from a challenge

Steps

• The user had 3 discussions in the My discussions(User - sdgunvfor(pw-T0pc0der@123)
• Registered to a new challenge(https://www.topcoder-dev.com/challenges/f65f8ffa-d698-4348-8213-61d5ebe8ac63)
• Created a new discussion
• So the count in My Discussions became 4
• Unregistered from the challenge

The My discussions count is still 4 but inside there are only 3 discussions

Screencast 2020-12-17.zip

Final Submission Guidelines

Git issue link: https://github.com/topcoder-platform/forums/issues/301