Unable to mark Task as done

Sometimes I'm unable to mark a task as done from the issue description, it's happening from the Release issue but I'm not sure if this is related to the fact that we have a lot of content on that description.

Steps

• Go to https://gitlab.com/gitlab-org/gitlab-ce/issues/21620
• Try to mark the task Publish the release blog post as done
• Refresh the page

Expected

• I should see the task item checked.

Actual

• The task item remains unchecked.

- [x] This task is inside a code block
- [ ] Another task with a duplicate name

• This task is outside a code block
• Another task with a duplicate name
• One last task

- [ ] One last task