As expected, when you send the Post Offer VEVRAA form to a candidate, the icon is only displayed for the specific job application, and not for other job applications belonging to the candidate.
For example, a candidate applies for a job, is sent the form, and submits it. However, they end up declining the job afterward. Six months later, the same candidate reapplies for another job, and their new job application doesn't display the icon. If the candidate gets the offer for the job, the recruiter needs to resend them the form.