diff --git a/litellm/proxy/management_endpoints/tag_management_endpoints.py b/litellm/proxy/management_endpoints/tag_management_endpoints.py
index 8e3061c2032..0e60820aab1 100644
--- a/litellm/proxy/management_endpoints/tag_management_endpoints.py
+++ b/litellm/proxy/management_endpoints/tag_management_endpoints.py
@@ -456,11 +456,8 @@ async def list_tags(
         dynamic_tag_rows = await prisma_client.db.litellm_dailytagspend.group_by(
             by=["tag"],
             where={"tag": {"not": None}},
-            # The old find_many(distinct=...) returned arbitrary timestamps from
-            # whichever row Prisma happened to pick. MIN/MAX give more meaningful
-            # values: earliest appearance and most recent activity.
-            _min={"created_at": True},
-            _max={"updated_at": True},
+            min={"created_at": True},
+            max={"updated_at": True},
         )
 
         dynamic_tag_config = [
@@ -468,8 +465,8 @@ async def list_tags(
                 "name": row["tag"],
                 "description": "This is just a spend tag that was passed dynamically in a request. It does not control any LLM models.",
                 "models": None,
-                "created_at": row["_min"]["created_at"].isoformat(),
-                "updated_at": row["_max"]["updated_at"].isoformat(),
+                "created_at": row["_min"]["created_at"],
+                "updated_at": row["_max"]["updated_at"],
             }
             for row in dynamic_tag_rows
             if row["tag"] not in stored_tag_names
diff --git a/tests/test_litellm/proxy/management_endpoints/test_tag_management_endpoints.py b/tests/test_litellm/proxy/management_endpoints/test_tag_management_endpoints.py
index f330b40282c..4b443f211ff 100644
--- a/tests/test_litellm/proxy/management_endpoints/test_tag_management_endpoints.py
+++ b/tests/test_litellm/proxy/management_endpoints/test_tag_management_endpoints.py
@@ -282,9 +282,9 @@ async def test_list_tags_with_dynamic_tags():
 
             # Setup dynamic tags via group_by — includes one that overlaps with stored
             mock_db.litellm_dailytagspend.group_by = AsyncMock(return_value=[
-                {"tag": "dynamic-tag-1", "_min": {"created_at": datetime(2025, 2, 1)}, "_max": {"updated_at": datetime(2025, 3, 1)}},
-                {"tag": "dynamic-tag-2", "_min": {"created_at": datetime(2025, 2, 2)}, "_max": {"updated_at": datetime(2025, 3, 2)}},
-                {"tag": "stored-tag", "_min": {"created_at": datetime(2025, 1, 1)}, "_max": {"updated_at": datetime(2025, 1, 1)}},  # duplicate, should be excluded
+                {"tag": "dynamic-tag-1", "_min": {"created_at": "2025-02-01T00:00:00Z"}, "_max": {"updated_at": "2025-03-01T00:00:00Z"}},
+                {"tag": "dynamic-tag-2", "_min": {"created_at": "2025-02-02T00:00:00Z"}, "_max": {"updated_at": "2025-03-02T00:00:00Z"}},
+                {"tag": "stored-tag", "_min": {"created_at": "2025-01-01T00:00:00Z"}, "_max": {"updated_at": "2025-01-01T00:00:00Z"}},  # duplicate, should be excluded
             ])
 
             headers = {"Authorization": "Bearer sk-1234"}