diff --git a/shared/libebm/PartitionOneDimensionalBoosting.cpp b/shared/libebm/PartitionOneDimensionalBoosting.cpp
index 8d9a1ade8..63a875705 100644
--- a/shared/libebm/PartitionOneDimensionalBoosting.cpp
+++ b/shared/libebm/PartitionOneDimensionalBoosting.cpp
@@ -369,7 +369,7 @@ static ErrorEbm Flatten(BoosterShell* const pBoosterShell,
                            EBM_ASSERT(iEdge <= cBins);
                            if(cBins == iEdge) {
                               // this cut would isolate the missing bin, but missing already has a cut
-                              break;
+                              return Error_IllegalParamVal;
                            }
                         }
                      }