This will happen if a participant's profile is set to "private". To check this:
  1. Fundraising > TeamRaiser > "Manage" next to the TeamRaiser in question
  2. Search for the affected participant and click on their name.
  3. Next to the links to the team page and participant page, it will say "Private / Configured" if the participant has set their profile to be private. It will say "Public / Default" if this is not the case.
  4. If this is not the intent of the participant, click on the button "Make Public"