Add a note about a bug

README.md

@@ -1 +1,19 @@
 # de_quoi_parle_le_monde
+
+### Bug
+
+In the `featured_article_snapshot_id` view, the field `featured_article_snapshot_id` is taken as if it was unique by row, but it is not. 
+
+This can be easily checked with this query :
+
+```sql
+SELECT * FROM (
+    SELECT featured_article_snapshot_id, json_group_array(snapshot_id), COUNT(*) as count
+    FROM snapshot_apparitions
+    WHERE is_main -- Not required
+    GROUP BY featured_article_snapshot_id
+)
+WHERE count > 1
+```
+
+Among other things it leads to "deadends" while browsing the UI, likely because the timestamp search and time diff relies on this false assumption.