diff --git a/python/graphstorm/gconstruct/transform.py b/python/graphstorm/gconstruct/transform.py
index 2a1a2f732b..40e1da2fa3 100644
--- a/python/graphstorm/gconstruct/transform.py
+++ b/python/graphstorm/gconstruct/transform.py
@@ -951,6 +951,7 @@ def call(self, feats):
                 feats = feats[:, :self.truncate_dim]
             else:
                 assert isinstance(feats, ExtMemArrayWrapper)
+                # Need to convert to in-memory array to make truncation possible
                 feats = feats.to_numpy()[:, :self.truncate_dim]
         return {self.feat_name: feats}