diff --git a/src/unitxt/operators.py b/src/unitxt/operators.py
index ac7ea090f..3e5035f17 100644
--- a/src/unitxt/operators.py
+++ b/src/unitxt/operators.py
@@ -628,9 +628,8 @@ def _get_random_pattern(self, pattern_distribution) -> str:
                 get_random().choices(
                     pattern_distribution["patterns"],
                     pattern_distribution["weights"],
-                    k=1,
+                    k=pattern_distribution["length"],
                 )
-                * pattern_distribution["length"]
             )
         return string_to_add
 
diff --git a/tests/test_operators.py b/tests/test_operators.py
index 2972c204d..dab2f1678 100644
--- a/tests/test_operators.py
+++ b/tests/test_operators.py
@@ -2016,7 +2016,7 @@ def test_augment_prefix_suffix_model_input(self):
             "\t\t " in output0
         ), f"Trailing whitespaces wrongly removed, yielding {output0}, although 'remove_existing_whitespaces' is False,"
         # weighted suffixes
-        suffixes_dict = {"Q": 2, "R": 2, "S": 2, "T": 8}
+        suffixes_dict = {"Q": 2, "R": 2, "S": 2, "T": 10}
         operator = AugmentPrefixSuffix(
             augment_model_input=True,
             suffixes=suffixes_dict,
@@ -2027,11 +2027,11 @@ def test_augment_prefix_suffix_model_input(self):
         assert (
             len(outputs) == 500
         ), f"outputs length {len(outputs)} is different from inputs length, which is 500."
-        actual_suffixes = [output["source"][-8:] for output in outputs]
+        actual_suffixes = [output["source"][-2:] for output in outputs]
         counter = Counter(actual_suffixes)
         assert (
-            counter["TTTTTTTT"] > 125
-        ), f'In a population of size 500, suffix "TTTTTTTT" is expected to be more frequent than {counter["T"]}'
+            counter["TT"] > counter["SS"]
+        ), f'In a population of size 500 , suffix "TT" ({counter["TT"]}) is expected to be more frequent than "SS" {counter["SS"]}'
 
         # just for code coverage of Augmentor.process_value and Augmentor.process
         class JustToCoverProcessValueOfAugmentor(Augmentor):