diff --git a/litellm/litellm_core_utils/get_model_cost_map.py b/litellm/litellm_core_utils/get_model_cost_map.py
index 0fc2be58b2d..69a19ffe6bf 100644
--- a/litellm/litellm_core_utils/get_model_cost_map.py
+++ b/litellm/litellm_core_utils/get_model_cost_map.py
@@ -852,6 +852,11 @@ def _merge_into_import_map(fetch: _ImportFetch, finalized: Mapping[str, object])
         for key, entry in remote
         if key not in fetch.loaded and key not in fetch.bundled
     }
+    added_since_import: Final = {
+        key: _merged_entry(current, entry, frozenset(current.keys()))
+        for key, entry in remote
+        if key not in fetch.loaded and _is_cost_entry(current := fetch.bundled.get(key)) and _is_cost_entry(entry)
+    }
     dropped: Final = tuple(
         key
         for key in fetch.loaded.keys() - finalized.keys()
@@ -859,7 +864,7 @@ def _merge_into_import_map(fetch: _ImportFetch, finalized: Mapping[str, object])
     )
     for live_entry, entry in updated_in_place:
         live_entry.update(entry)
-    fetch.bundled.update({**replaced, **added})
+    fetch.bundled.update({**replaced, **added, **added_since_import})
     for key in dropped:
         fetch.bundled.pop(key, None)
     GetModelCostMap._snapshot_loaded_catalog(  # pyright: ignore[reportPrivateUsage]  # same module
diff --git a/tests/unit/litellm_core_utils/test_get_model_cost_map.py b/tests/unit/litellm_core_utils/test_get_model_cost_map.py
index d618266209c..cc62fbf4eae 100644
--- a/tests/unit/litellm_core_utils/test_get_model_cost_map.py
+++ b/tests/unit/litellm_core_utils/test_get_model_cost_map.py
@@ -1304,6 +1304,36 @@ def test_a_router_built_before_the_remote_map_lands_prices_its_models_from_the_r
     assert litellm.get_model_info("openai/gpt-4o")["input_cost_per_token"] == remote_price
 
 
+def test_a_router_built_before_the_remote_map_lands_serves_a_bare_model_only_the_remote_map_knows(
+    isolated_litellm_cost_state, monkeypatch
+):
+    import litellm
+    from litellm.litellm_core_utils.get_model_cost_map import load_model_cost_map_at_import
+
+    client, retry_started, release = _rate_limited_then_held_client(_remote_map_with("claude-remote-only-test"))
+    try:
+        monkeypatch.setattr(
+            litellm, "model_cost", load_model_cost_map_at_import(url=_URL, client=client, sleep=lambda _: None)
+        )
+        assert retry_started.wait(timeout=10)
+        router = litellm.Router(
+            model_list=[
+                {
+                    "model_name": "remote-only",
+                    "litellm_params": {"model": "claude-remote-only-test", "api_key": "sk-test"},
+                }
+            ],
+            ignore_invalid_deployments=True,
+        )
+        served_before_the_remote_map = len(router.model_list)
+    finally:
+        _finish_fetch(release)
+
+    assert served_before_the_remote_map == 0
+    assert [deployment["model_name"] for deployment in router.model_list] == ["remote-only"]
+    assert litellm.get_model_info("claude-remote-only-test")["litellm_provider"] == "anthropic"
+
+
 def test_a_partial_edit_made_before_the_remote_map_lands_keeps_only_the_fields_it_changed(
     isolated_litellm_cost_state, monkeypatch
 ):