diff --git a/src/ert/config/summary_config.py b/src/ert/config/summary_config.py
index 73d6151b598..dfa2804f607 100644
--- a/src/ert/config/summary_config.py
+++ b/src/ert/config/summary_config.py
@@ -26,6 +26,7 @@ class SummaryConfig(ResponseConfig):
     def __post_init__(self) -> None:
         if isinstance(self.refcase, list):
             self.refcase = {datetime.fromisoformat(val) for val in self.refcase}
+        self.keys = sorted(set(self.keys))
         if len(self.keys) < 1:
             raise ValueError("SummaryConfig must be given at least one key")
 
diff --git a/tests/integration_tests/test_storage_migration.py b/tests/integration_tests/test_storage_migration.py
index ad2fdc7afdb..7b0d552cdb1 100644
--- a/tests/integration_tests/test_storage_migration.py
+++ b/tests/integration_tests/test_storage_migration.py
@@ -50,9 +50,6 @@ def test_that_storage_matches(tmp_path, source_root, snapshot, monkeypatch):
 
             # We need to normalize some irrelevant details:
             experiment.response_configuration["summary"].refcase = {}
-            experiment.response_configuration["summary"].keys = sorted(
-                set(experiment.response_configuration["summary"].keys)
-            )
             experiment.parameter_configuration["PORO"].mask_file = ""
 
             snapshot.assert_match(
diff --git a/tests/unit_tests/config/test_summary_config.py b/tests/unit_tests/config/test_summary_config.py
index 70158f4f3df..d04ab47bd2d 100644
--- a/tests/unit_tests/config/test_summary_config.py
+++ b/tests/unit_tests/config/test_summary_config.py
@@ -25,3 +25,10 @@ def test_rading_empty_summaries_raises(wopr_summary):
     unsmry.to_file("CASE.UNSMRY")
     with pytest.raises(ValueError, match="Did not find any summary values"):
         SummaryConfig("summary", "CASE", ["WWCT:OP1"], None).read_from_file(".", 0)
+
+
+def test_summary_config_normalizes_list_of_keys():
+    assert SummaryConfig("summary", "CASE", ["FOPR", "WOPR", "WOPR"]).keys == [
+        "FOPR",
+        "WOPR",
+    ]
diff --git a/tests/unit_tests/storage/test_local_storage.py b/tests/unit_tests/storage/test_local_storage.py
index 9700eb0cf57..8a2da904883 100644
--- a/tests/unit_tests/storage/test_local_storage.py
+++ b/tests/unit_tests/storage/test_local_storage.py
@@ -174,7 +174,7 @@ def test_writing_to_read_only_storage_raises(tmp_path):
             input_file=st.text(
                 alphabet=st.characters(min_codepoint=65, max_codepoint=90)
             ),
-            keys=st.lists(summary_keys, max_size=3, min_size=1),
+            keys=summary_keys,
             refcase=st.just(None),
         ),
     ),