diff --git a/iib/workers/tasks/build_merge_index_image.py b/iib/workers/tasks/build_merge_index_image.py
index 7b8906ceb..07e116946 100644
--- a/iib/workers/tasks/build_merge_index_image.py
+++ b/iib/workers/tasks/build_merge_index_image.py
@@ -625,7 +625,7 @@ def parse_version(version):
     # Validate the bundles and bundle_images lenght
     if len(bundle_version_names) != len(bundles):
         uniq_verions = [x[2] for x in bundle_version_names]
-        diff = set(bundles) - set(uniq_verions)
+        diff = sorted(set(bundles) - set(uniq_verions))
         raise IIBError(f"Failed to retrieve bundles by semver, missing bundle images: {diff}")
 
     # Retrieve the latest version of all bundle packages.
diff --git a/tests/test_workers/test_tasks/test_build_merge_index_image.py b/tests/test_workers/test_tasks/test_build_merge_index_image.py
index c1c1fb775..f6af4bc20 100644
--- a/tests/test_workers/test_tasks/test_build_merge_index_image.py
+++ b/tests/test_workers/test_tasks/test_build_merge_index_image.py
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 import json
 import os
+import re
 import stat
 from unittest import mock
 
@@ -1085,7 +1086,7 @@ def test_get_bundles_latest_version(bundle_images, expected):
                     'version': '1.2.34',
                 },
             ],
-            set(["operator2@sha256:1000"]),
+            ["operator2@sha256:1000"],
         ),
         (
             [
@@ -1110,16 +1111,14 @@ def test_get_bundles_latest_version(bundle_images, expected):
                     'version': '3.0.0',
                 },
             ],
-            set(
-                [
-                    "missing-operator@sha256:1234",
-                    "missing-operator@sha256:0001",
-                ]
-            ),
+            [
+                "missing-operator@sha256:0001",
+                "missing-operator@sha256:1234",
+            ],
         ),
     ],
 )
 def test_get_bundles_latest_version_missing_bundles(bundles, bundle_images, diff_bundles):
     err = f"Failed to retrieve bundles by semver, missing bundle images: {diff_bundles}"
-    with pytest.raises(IIBError, match=err):
+    with pytest.raises(IIBError, match=re.escape(err)):
         build_merge_index_image.get_bundles_latest_version(bundles, bundle_images)