diff --git a/src/Microsoft.ML.Data/Data/Conversion.cs b/src/Microsoft.ML.Data/Data/Conversion.cs
index cf48c3f295..57b27c9184 100644
--- a/src/Microsoft.ML.Data/Data/Conversion.cs
+++ b/src/Microsoft.ML.Data/Data/Conversion.cs
@@ -950,8 +950,8 @@ public void Convert(in BL src, ref SB dst)
         public void Convert(in R8 src, ref TX dst) => dst = src.ToString("G17", CultureInfo.InvariantCulture).AsMemory();
         public void Convert(in BL src, ref TX dst) => dst = src.ToString().AsMemory();
         public void Convert(in TS src, ref TX dst) => dst = string.Format("{0:c}", src).AsMemory();
-        public void Convert(in DT src, ref TX dst) => string.Format("{0:o}", src).AsMemory();
-        public void Convert(in DZ src, ref TX dst) => string.Format("{0:o}", src).AsMemory();
+        public void Convert(in DT src, ref TX dst) => dst = string.Format("{0:o}", src).AsMemory();
+        public void Convert(in DZ src, ref TX dst) => dst = string.Format("{0:o}", src).AsMemory();
         #endregion ToTX
 
         #region ToBL
@@ -1733,4 +1733,4 @@ public void Convert(in TX src, ref SB dst)
         public void Convert(in DT src, ref DT dst) => dst = src;
         #endregion ToDT
     }
-}
\ No newline at end of file
+}