diff --git a/python/lsst/ip/isr/overscan.py b/python/lsst/ip/isr/overscan.py
index 436c004c9..c5746c840 100644
--- a/python/lsst/ip/isr/overscan.py
+++ b/python/lsst/ip/isr/overscan.py
@@ -266,12 +266,12 @@ def correctOverscan(self, exposure, amp, imageBBox, overscanBBox,
             )
         else:
             median = np.ma.median(np.ma.masked_where(overscanMask, overscanArray))
-            bad = np.where(np.abs(overscanArray - median) > self.config.maxDeviation)
+            bad = np.where((np.abs(overscanArray - median) > self.config.maxDeviation) & (~overscanMask))
             # Mark the bad pixels as BAD.
             overscanImage.mask.array[bad] = overscanImage.mask.getPlaneBitMask("BAD")
 
             # Check for completely masked row/column.
-            if maskedRowColumnGrowSize > 0:
+            if maskedRowColumnGrowSize > 0 and len(bad) > 0:
                 if isTransposed:
                     axis = 0
                     nComp = overscanArray.shape[0]
diff --git a/tests/test_overscanCorrection.py b/tests/test_overscanCorrection.py
index 53eb3f19b..02393ba72 100644
--- a/tests/test_overscanCorrection.py
+++ b/tests/test_overscanCorrection.py
@@ -543,6 +543,7 @@ def test_bleedParallelOverscanCorrection(self):
 
                     configParallel = ipIsr.overscan.ParallelOverscanCorrectionTask.ConfigClass()
                     configParallel.parallelOverscanMaskGrowSize = 1
+                    configParallel.parallelOverscanMaskedColumnGrowSize = 0
                     configParallel.fitType = fitType
 
                     parallelOverscanTask = ipIsr.overscan.ParallelOverscanCorrectionTask(