diff --git a/frontend/src/pages/Trends.tsx b/frontend/src/pages/Trends.tsx
index 2fead84..433f622 100644
--- a/frontend/src/pages/Trends.tsx
+++ b/frontend/src/pages/Trends.tsx
@@ -103,10 +103,10 @@ function TrendCard({ trend, onClick }: { trend: TrendSummary; onClick: () => voi
       )}
       {expanded && (
         <div className="mt-2 space-y-1 text-xs">
-          {trend.top_supporting_evidence?.map((e, i) => (
+          {[...new Set(trend.top_supporting_evidence ?? [])].map((e, i) => (
             <EvidenceRef key={i} id={e} direction="supporting" />
           ))}
-          {trend.top_opposing_evidence?.map((e, i) => (
+          {[...new Set(trend.top_opposing_evidence ?? [])].map((e, i) => (
             <EvidenceRef key={i} id={e} direction="opposing" />
           ))}
         </div>
diff --git a/services/aggregation/worker.py b/services/aggregation/worker.py
index 4e3f66d..39cab62 100644
--- a/services/aggregation/worker.py
+++ b/services/aggregation/worker.py
@@ -687,8 +687,8 @@ def assemble_trend_with_evidence(
     config = EvidenceRankConfig(max_refs=max_evidence)
     supporting_ranked, opposing_ranked = rank_evidence_detailed(signals, config)
 
-    supporting = [r.document_id for r in supporting_ranked]
-    opposing = [r.document_id for r in opposing_ranked]
+    supporting = list(dict.fromkeys(r.document_id for r in supporting_ranked))
+    opposing = list(dict.fromkeys(r.document_id for r in opposing_ranked))
 
     catalysts, risks = extract_catalysts_and_risks(impacts, signals)