diff --git a/services/dataProcessor.ts b/services/dataProcessor.ts
index 3a16687..3669ae1 100644
--- a/services/dataProcessor.ts
+++ b/services/dataProcessor.ts
@@ -1654,7 +1654,19 @@ export const calculateForecastViewData = (
     // Use referenceData if provided (for global weights), otherwise fallback to rawData
     const seasonalitySource = referenceData || rawData;
     const historicalData = seasonalitySource.filter(r => r.year < 2026);
-    const data2026 = seasonalitySource.filter(r => r.year === 2026);
+
+    // IMPORTANT: Actuals for 2026 must be strictly scoped to the forecast region
+    // to avoid mixing UK stats into Pan-EU or vice-versa.
+    const isForecastUKMode = filters?.customer?.includes('Amazon UK');
+    const data2026 = rawData.filter(r => {
+        if (r.year !== 2026) return false;
+        if (isForecastUKMode) {
+            return r.customer === 'Amazon UK';
+        } else {
+            // In Pan-EU mode, explicitly exclude UK units even if they are in the dataset
+            return r.customer !== 'Amazon UK';
+        }
+    });
 
     // Calculate Seasonality weights for 2025
     const getWeightsInfo = (records: SalesRecord[]): { weights: number[]; monthsCount: number } | null => {