diff --git a/app/api/trading/execute/route.ts b/app/api/trading/execute/route.ts
index 5b05c4e..fd47e26 100644
--- a/app/api/trading/execute/route.ts
+++ b/app/api/trading/execute/route.ts
@@ -171,7 +171,7 @@ export async function POST(request: NextRequest): Promise<NextResponse<ExecuteTr
           timeframe: timeframe,
           signalPrice: currentPrice,
           signalQualityScore: qualityResult.score, // CRITICAL: Real quality score for analysis
-          signalQualityVersion: timeframe === '1' ? null : 'v9', // 1-minute data = pure market sampling, no indicator version
+          signalQualityVersion: timeframe === '1' ? undefined : 'v9', // 1-minute data = pure market sampling, no indicator version
           minScoreRequired: minQualityScore,
           scoreBreakdown: { reasons: qualityResult.reasons },
           indicatorVersion: body.indicatorVersion || 'v5',