They describe a leaderboard built from server members' shared gaming activity, while actual rollout remains unconfirmed.
When It Appears
“Last updated {timestamp}” can appear on a server view that ranks shared gaming activity and shows a timed competition when Discord displays the timestamp for the leaderboard statistics' latest refresh.
What It Means
When “Last updated {timestamp}” is shown, the current step is presenting the timestamp for the leaderboard statistics' latest refresh.
A user who saw “Last updated {timestamp}” in Discord is likely searching to confirm that it means the timestamp for the leaderboard statistics' latest refresh, where it appears, and which state it describes.