If you are on 1.5 App Store release, the circle check means they have nip05 verification(nostr address) and the person checkmark means you follow them, there’s a few different person checkmarks. One means you follow them, one means they follow you, and one means you follow each other. If you are on 1.6 TestFlight, the circle checkmarks will not show up in the feed, they will only load if you go into someone’s profile.