@JGayman this may seem like a silly question, and I apologize. However I've made this mistake before so I'm sharing it with you now. Is the team member sure they're searching under Owner = Any like this:
Another idea is that it's a glitch, and maybe they need to sign out and sign in to refresh the account?
Final idea: Have you contacted Support? They may have insight as well.
Good luck!
Did my answer help? Please "mark as a solution" to help others find answers. Plus I really appreciate it!