diff --git a/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/cacheSettingsUtils.test.ts b/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/cacheSettingsUtils.test.ts
index 86a20f0ba2d..6e63f9e6dad 100644
--- a/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/cacheSettingsUtils.test.ts
+++ b/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/cacheSettingsUtils.test.ts
@@ -51,10 +51,6 @@ describe("buildCachePayload", () => {
       port: "6379",
       ssl: false,
       ssl_check_hostname: false,
-      // semantic caching is off, so its fields are explicitly cleared
-      similarity_threshold: null,
-      redis_semantic_cache_embedding_model: null,
-      semantic_cache_scope: null,
     });
     expect(payload).not.toHaveProperty("redis_type");
     expect(payload).not.toHaveProperty("username");
@@ -84,15 +80,15 @@ describe("buildCachePayload", () => {
     expect(payload.similarity_threshold).toBe(0.9);
   });
 
-  it("should send null for semantic fields when semantic caching is disabled, so turning it off clears them", () => {
+  it("should omit semantic fields when semantic caching is disabled, even if they hold values", () => {
     const payload = buildCachePayload(
       "node",
-      { similarity_threshold: 0.9 },
+      { similarity_threshold: 0.9, redis_semantic_cache_embedding_model: "text-embedding-3-small" },
       { forTesting: false, semanticEnabled: false },
     );
     expect(payload.type).toBe("redis");
-    expect(payload.similarity_threshold).toBe(null);
-    expect(payload.redis_semantic_cache_embedding_model).toBe(null);
+    expect(payload).not.toHaveProperty("similarity_threshold");
+    expect(payload).not.toHaveProperty("redis_semantic_cache_embedding_model");
   });
 
   it("should send the semantic cache scope only when semantic caching is enabled", () => {
@@ -102,14 +98,14 @@ describe("buildCachePayload", () => {
       { forTesting: false, semanticEnabled: true },
     );
     expect(enabled.semantic_cache_scope).toBe("end_user");
-    // Disabled sends an explicit null rather than omitting the field, so a scope
-    // configured earlier is cleared on the server instead of silently surviving.
+    // Disabled must omit the scope rather than send null: the backend rejects a null scope
+    // when it rebuilds the cache, while an omitted one falls back to its default.
     const disabled = buildCachePayload(
       "node",
       { semantic_cache_scope: "end_user" },
       { forTesting: false, semanticEnabled: false },
     );
-    expect(disabled.semantic_cache_scope).toBe(null);
+    expect(disabled).not.toHaveProperty("semantic_cache_scope");
   });
 
   it("should keep type redis when testing with semantic caching enabled so the test endpoint accepts it", () => {
diff --git a/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/cacheSettingsUtils.ts b/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/cacheSettingsUtils.ts
index 1571d31f088..7f850d19e9c 100644
--- a/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/cacheSettingsUtils.ts
+++ b/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/cacheSettingsUtils.ts
@@ -94,10 +94,11 @@ export const buildCachePayload = (
   const type = !forTesting && semanticEnabled ? "redis-semantic" : "redis";
 
   const entries = CACHE_FIELDS.filter((field) => isFieldVisible(field, redisType)).flatMap((field) => {
-    // Semantic fields are always visible now, so clearing the toggle has to send an
-    // explicit null - omitting them would leave the previous values on the server.
+    // Semantic fields are always visible now, so leave them out when the toggle is off. The
+    // backend stores the payload as sent, which already clears them; an explicit null would
+    // reach Cache(semantic_cache_scope=None) and fail both the save and the connection test.
     if (field.section === "semantic" && !semanticEnabled) {
-      return [[field.name, null] as [string, CacheSavePayloadValue]];
+      return [];
     }
     const value = saveValueForField(field, values[field.name]);
     return value === undefined ? [] : [[field.name, value] as [string, CacheSavePayloadValue]];
diff --git a/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/index.integration.test.tsx b/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/index.integration.test.tsx
index 26ff5179e17..0d1da4dc8ce 100644
--- a/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/index.integration.test.tsx
+++ b/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/index.integration.test.tsx
@@ -61,10 +61,6 @@ describe("CacheSettings advanced settings round-trip", () => {
       namespace: "prod-ns",
       ttl: 300,
       max_connections: 50,
-      // semantic caching is off, so its fields are cleared explicitly
-      similarity_threshold: null,
-      redis_semantic_cache_embedding_model: null,
-      semantic_cache_scope: null,
     });
   });
 
diff --git a/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/index.test.tsx b/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/index.test.tsx
index 80ab2c86ca2..196154bbaf6 100644
--- a/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/index.test.tsx
+++ b/ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_settings/index.test.tsx
@@ -151,10 +151,6 @@ describe("CacheSettings", () => {
           port: "6379",
           ssl: false,
           ssl_check_hostname: false,
-          // semantic caching is off, so its fields are cleared explicitly
-          similarity_threshold: null,
-          redis_semantic_cache_embedding_model: null,
-          semantic_cache_scope: null,
         }),
       );
     });