They describe a leaderboard built from server members' shared gaming activity, while actual rollout remains unconfirmed.
When It Appears
“Not enough data” can appear on a server view that ranks shared gaming activity and shows a timed competition when Discord displays the state where there is insufficient shared activity to calculate the leaderboard.
When “Not enough data” is shown, the current step is presenting the state where there is insufficient shared activity to calculate the leaderboard.
Search Intent
A user who saw “Not enough data” in Discord is likely searching to confirm that it means the state where there is insufficient shared activity to calculate the leaderboard, where it appears, and which state it describes.