diff --git a/litellm/proxy/management_endpoints/internal_user_endpoints.py b/litellm/proxy/management_endpoints/internal_user_endpoints.py
index ac85e432d8f..10c11119006 100644
--- a/litellm/proxy/management_endpoints/internal_user_endpoints.py
+++ b/litellm/proxy/management_endpoints/internal_user_endpoints.py
@@ -22,7 +22,7 @@ from typing import Any, Final, Literal, Protocol, cast, overload
 
 import fastapi
 from fastapi import APIRouter, Depends, Header, HTTPException, Request, status
-from pydantic import TypeAdapter
+from pydantic import TypeAdapter, ValidationError
 
 import litellm
 from litellm._logging import verbose_proxy_logger
@@ -88,6 +88,7 @@ from litellm.types.proxy.management_endpoints.scim_v2 import (
     SCIM_ENTITLEMENTS_METADATA_KEY,
     SCIM_ROLES_METADATA_KEY,
 )
+from litellm.types.utils import BudgetConfig
 
 if TYPE_CHECKING:
     from prisma import models as prisma_models
@@ -98,7 +99,8 @@ if TYPE_CHECKING:
     from litellm.proxy.utils import ProxyLogging
 
 router: Final = APIRouter()
-_USER_MODEL_BUDGET_ADAPTER: Final = TypeAdapter(GenericBudgetConfigType)
+_USER_MODEL_BUDGET_ADAPTER: Final = TypeAdapter(dict[str, float | BudgetConfig])
+_USER_BUDGET_CACHE_INVALIDATION_BATCH_SIZE: Final = 50
 
 
 def _user_table(
@@ -1257,7 +1259,10 @@ def _update_internal_user_params(data_json: dict, data: UpdateUserRequest | Upda
                 non_default_values[k] = v
         elif k == "model_max_budget":
             if k in fields_set:
-                _USER_MODEL_BUDGET_ADAPTER.validate_python({} if v is None else v)
+                try:
+                    _USER_MODEL_BUDGET_ADAPTER.validate_python({} if v is None else v)
+                except ValidationError as exc:
+                    raise HTTPException(status_code=400, detail=str(exc)) from exc
                 non_default_values[k] = {} if v is None else v
         elif (
             v is not None
@@ -1888,10 +1893,13 @@ async def bulk_user_update(
             )
 
             if "model_max_budget" in non_default_values:
-                await evict_and_broadcast(
-                    cache_keys=tuple(user.user_id for user in all_users_in_db),
-                    user_api_key_cache=user_api_key_cache,
-                )
+                for start in range(0, len(all_users_in_db), _USER_BUDGET_CACHE_INVALIDATION_BATCH_SIZE):
+                    await asyncio.gather(
+                        *(
+                            evict_and_broadcast(cache_keys=(user.user_id,), user_api_key_cache=user_api_key_cache)
+                            for user in all_users_in_db[start : start + _USER_BUDGET_CACHE_INVALIDATION_BATCH_SIZE]
+                        )
+                    )
 
             # Create individual success results
             for user in all_users_in_db:
diff --git a/tests/test_litellm/proxy/management_endpoints/test_internal_user_endpoints.py b/tests/test_litellm/proxy/management_endpoints/test_internal_user_endpoints.py
index 2f665f4acd3..92b1ab1586d 100644
--- a/tests/test_litellm/proxy/management_endpoints/test_internal_user_endpoints.py
+++ b/tests/test_litellm/proxy/management_endpoints/test_internal_user_endpoints.py
@@ -5,7 +5,7 @@ from typing import Final
 
 import pytest
 from fastapi.testclient import TestClient
-from pydantic import ValidationError
+from fastapi import HTTPException
 from pytest_mock import MockerFixture
 
 
@@ -2147,7 +2147,7 @@ def test_update_internal_user_params_preserves_model_budget_presence_and_neighbo
         "user_alias": "Spruce",
     }
 
-    replacement: Final = {"model-spruce": {"budget_limit": 0, "time_period": "1d"}}
+    replacement: Final = {"model-spruce": {"budget_limit": 0, "time_period": "1d"}, "model-birch": 5.0, "model-cedar": 0}
     request: Final = UpdateUserRequest(
         user_id="user-spruce",
         model_max_budget=replacement,
@@ -2168,8 +2168,9 @@ def test_update_internal_user_params_preserves_model_budget_presence_and_neighbo
 def test_update_internal_user_params_rejects_invalid_model_budget(invalid_budget: dict[str, object]) -> None:
     request: Final = UpdateUserRequest(user_id="user-spruce", model_max_budget=invalid_budget)
 
-    with pytest.raises(ValidationError):
+    with pytest.raises(HTTPException) as exc:
         _update_internal_user_params(data_json=request.model_dump(exclude_unset=True), data=request)
+    assert exc.value.status_code == 400
 
 
 @pytest.mark.asyncio
@@ -2228,6 +2229,16 @@ async def test_bulk_user_model_budget_clear_serializes_and_refreshes_cache(mocke
         new_callable=mocker.AsyncMock,
     )
 
+    with pytest.raises(HTTPException) as exc:
+        await bulk_user_update(
+            data=BulkUpdateUserRequest(all_users=True, user_updates={"model_max_budget": {"model-spruce": "invalid"}}),
+            user_api_key_dict=UserAPIKeyAuth(user_id="admin-spruce", user_role=LitellmUserRoles.PROXY_ADMIN),
+            litellm_changed_by=None,
+        )
+    assert exc.value.status_code == 400
+    prisma_client.db.litellm_usertable.update_many.assert_not_called()
+    assert await cache.async_get_cache(key=saved_user.user_id, model_type=LiteLLM_UserTable) == saved_user
+
     response: Final = await bulk_user_update(
         data=BulkUpdateUserRequest(all_users=True, user_updates={"model_max_budget": None}),
         user_api_key_dict=UserAPIKeyAuth(user_id="admin-spruce", user_role=LitellmUserRoles.PROXY_ADMIN),