diff --git a/CI/physmon/reference/performance_amvf_orthogonal_hist.root b/CI/physmon/reference/performance_amvf_orthogonal_hist.root
index 107d20ec699..fc736ceebfb 100644
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diff --git a/CI/physmon/reference/performance_amvf_seeded_hist.root b/CI/physmon/reference/performance_amvf_seeded_hist.root
index 79080e2885f..51ec061e3ba 100644
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diff --git a/CI/physmon/reference/performance_amvf_truth_estimated_hist.root b/CI/physmon/reference/performance_amvf_truth_estimated_hist.root
index be94b29d7a5..29269766f05 100644
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diff --git a/CI/physmon/reference/performance_amvf_truth_smeared_hist.root b/CI/physmon/reference/performance_amvf_truth_smeared_hist.root
index c8a88e740fb..b64291db95c 100644
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diff --git a/CI/physmon/reference/performance_amvf_ttbar_hist.root b/CI/physmon/reference/performance_amvf_ttbar_hist.root
index 0919cdec59c..0c51e6d36d8 100644
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diff --git a/Core/include/Acts/Vertexing/AdaptiveMultiVertexFinder.ipp b/Core/include/Acts/Vertexing/AdaptiveMultiVertexFinder.ipp
index f3f2151153e..f762c0aac9f 100644
--- a/Core/include/Acts/Vertexing/AdaptiveMultiVertexFinder.ipp
+++ b/Core/include/Acts/Vertexing/AdaptiveMultiVertexFinder.ipp
@@ -522,20 +522,21 @@ auto Acts::AdaptiveMultiVertexFinder<vfitter_t, sfinder_t>::isMergedVertex(
 
     double significance = 0;
     if (not m_cfg.do3dSplitting) {
-      // Use only z significance
-      if (sumCovZ > 0.) {
-        significance = std::abs(deltaZPos) / std::sqrt(sumCovZ);
-      } else {
-        return true;
+      if (sumCovZ <= 0) {
+        // TODO FIXME this should never happen
+        continue;
       }
+      // Use only z significance
+      significance = std::abs(deltaZPos) / std::sqrt(sumCovZ);
     } else {
       // Use full 3d information for significance
       SymMatrix4 sumCov = candidateCov + otherCov;
-      if (auto sumCovInverse = safeInverse(sumCov); sumCovInverse) {
-        significance = std::sqrt(deltaPos.dot(*sumCovInverse * deltaPos));
-      } else {
-        return true;
+      auto sumCovInverse = safeInverse(sumCov);
+      if (!sumCovInverse) {
+        // TODO FIXME this should never happen
+        continue;
       }
+      significance = std::sqrt(deltaPos.dot(*sumCovInverse * deltaPos));
     }
     if (significance < m_cfg.maxMergeVertexSignificance) {
       return true;