diff --git a/draco/analysis/delay.py b/draco/analysis/delay.py
index 7a9b8b7a7..5ddd54c30 100644
--- a/draco/analysis/delay.py
+++ b/draco/analysis/delay.py
@@ -610,10 +610,9 @@ def _cut_data(
 
         # Remove the mean from the data before estimating the spectrum
         if self.remove_mean:
-            dmean = (data * weight).mean(axis=0) * tools.invert_no_zero(
-                weight.mean(axis=0)
-            )
-            data = data - dmean[np.newaxis, :]
+            # Do not apply this in place to make sure we don't modify
+            # the input data
+            data = data - np.mean(data, axis=0)[np.newaxis]
 
         # If there are no non-zero data entries skip
         if (data == 0.0).all():