diff --git a/ludwig/utils/strings_utils.py b/ludwig/utils/strings_utils.py
index 78152f6d823..a59b7ac4cc6 100644
--- a/ludwig/utils/strings_utils.py
+++ b/ludwig/utils/strings_utils.py
@@ -259,7 +259,7 @@ def build_sequence_matrix(
     max_length = length_limit
 
     def pad(vector):
-        sequence = np.full((max_length,),
+        sequence = np.full((int(max_length),),
                            inverse_vocabulary[padding_symbol],
                            dtype=format_dtype)
         limit = min(vector.shape[0], max_length)