diff --git a/.changeset/cors-allow-if-match.md b/.changeset/cors-allow-if-match.md
new file mode 100644
index 0000000000..ad84a7e414
--- /dev/null
+++ b/.changeset/cors-allow-if-match.md
@@ -0,0 +1,13 @@
+---
+'@objectstack/plugin-hono-server': patch
+'@objectstack/hono': patch
+---
+
+CORS default `allowHeaders` now includes `If-Match`. The REST record update
+accepts the OCC token as an `If-Match` header (objectui's record-level inline
+edit sends it on every save), but the preflight allow-list omitted it — so on
+any split-origin deployment (console dev server against a backend on another
+origin) the browser failed the preflight and every inline-edit save died with
+"Failed to fetch". Found live while dogfooding objectui#2572; same
+split-origin failure class as the #2548 Bearer fixes. Explicit user-supplied
+`allowHeaders` still win unchanged.
diff --git a/packages/adapters/hono/src/index.ts b/packages/adapters/hono/src/index.ts
index 9dd4469076..920109559f 100644
--- a/packages/adapters/hono/src/index.ts
+++ b/packages/adapters/hono/src/index.ts
@@ -186,7 +186,9 @@ export function createHonoApp(options: ObjectStackHonoOptions): Hono {
       app.use('*', cors({
         origin: origin as any,
         allowMethods: corsOpts.methods || ['GET', 'POST', 'PUT', 'DELETE', 'PATCH', 'HEAD', 'OPTIONS'],
-        allowHeaders: corsOpts.allowHeaders || ['Content-Type', 'Authorization', 'X-Requested-With', 'X-Tenant-ID', 'X-Environment-Id'],
+        // Keep in sync with plugin-hono-server's defaultAllowHeaders — `If-Match`
+        // carries the OCC token on cross-origin record PATCHes (objectui#2572).
+        allowHeaders: corsOpts.allowHeaders || ['Content-Type', 'Authorization', 'X-Requested-With', 'X-Tenant-ID', 'X-Environment-Id', 'If-Match'],
         exposeHeaders,
         credentials,
         maxAge,
diff --git a/packages/plugins/plugin-hono-server/src/hono-plugin.test.ts b/packages/plugins/plugin-hono-server/src/hono-plugin.test.ts
index 43f8f9b7a7..f9f52efbc8 100644
--- a/packages/plugins/plugin-hono-server/src/hono-plugin.test.ts
+++ b/packages/plugins/plugin-hono-server/src/hono-plugin.test.ts
@@ -255,6 +255,18 @@ describe('HonoServerPlugin', () => {
             expect(corsConfigCapture.last.allowHeaders).toContain('Authorization');
         });
 
+        it('should allow If-Match by default (OCC token on cross-origin record PATCHes)', async () => {
+            corsConfigCapture.last = undefined;
+
+            const plugin = new HonoServerPlugin();
+            await plugin.init(context as PluginContext);
+
+            // objectui#2572 dogfood find: the record-level inline edit sends the
+            // OCC token as an `If-Match` header; a preflight that doesn't allow
+            // it makes every split-origin save fail with "Failed to fetch".
+            expect(corsConfigCapture.last.allowHeaders).toContain('If-Match');
+        });
+
         it('should merge user-supplied exposeHeaders with set-auth-token default', async () => {
             corsConfigCapture.last = undefined;
 
diff --git a/packages/plugins/plugin-hono-server/src/hono-plugin.ts b/packages/plugins/plugin-hono-server/src/hono-plugin.ts
index 7db54bd902..b6ea84ca8e 100644
--- a/packages/plugins/plugin-hono-server/src/hono-plugin.ts
+++ b/packages/plugins/plugin-hono-server/src/hono-plugin.ts
@@ -279,7 +279,12 @@ export class HonoServerPlugin implements Plugin {
                 // the better-auth `bearer()` plugin can deliver rotated
                 // session tokens to cross-origin clients (see plugin-auth).
                 // User-supplied exposeHeaders are merged with this default.
-                const defaultAllowHeaders = ['Content-Type', 'Authorization', 'X-Requested-With', 'X-Tenant-ID', 'X-Environment-Id'];
+                // `If-Match` carries the OCC token on record PATCHes (objectui's
+                // record-level inline edit, REST `update` with `ifMatch`) — without
+                // it in the preflight allow-list, every cross-origin save fails in
+                // the browser with "Failed to fetch" (objectui#2572 dogfood find;
+                // same split-origin class as the #2548 Bearer fixes).
+                const defaultAllowHeaders = ['Content-Type', 'Authorization', 'X-Requested-With', 'X-Tenant-ID', 'X-Environment-Id', 'If-Match'];
                 const defaultExposeHeaders = ['set-auth-token'];
                 const allowHeaders = corsOpts.allowHeaders ?? defaultAllowHeaders;
                 const exposeHeaders = Array.from(new Set([