diff --git a/CHANGES.rst b/CHANGES.rst
index 20627b3b..da861c5c 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,6 +1,14 @@
-1.4.0 (unreleased)
+1.4.1 (unreleased)
 ==================
 
+Bug Fixes
+---------
+
+jump
+~~~~
+
+- Added statement to prevent the number of cores used in multiprocessing from
+  being larger than the number of rows. This was causing some CI tests to fail. [#176]
 
 1.4.0 (2023-06-27)
 ==================
diff --git a/src/stcal/jump/jump.py b/src/stcal/jump/jump.py
index c6ad57da..250d1ebe 100644
--- a/src/stcal/jump/jump.py
+++ b/src/stcal/jump/jump.py
@@ -246,7 +246,8 @@ def detect_jumps(frames_per_group, data, gdq, pdq, err,
         n_slices = max_available // 2 or 1
     elif max_cores == 'all':
         n_slices = max_available
-
+    # Make sure we don't have more slices than rows.
+    n_slices = min(n_rows, n_slices)
     if n_slices == 1:
         gdq, row_below_dq, row_above_dq, total_primary_crs, stddev = \
             twopt.find_crs(data, gdq, readnoise_2d, rejection_thresh,