diff --git a/src/hooks/auto-update-checker/checker/cached-version.test.ts b/src/hooks/auto-update-checker/checker/cached-version.test.ts
index 6a6790134..352de6d19 100644
--- a/src/hooks/auto-update-checker/checker/cached-version.test.ts
+++ b/src/hooks/auto-update-checker/checker/cached-version.test.ts
@@ -4,7 +4,10 @@ import { tmpdir } from "node:os"
 import { join } from "node:path"
 
 // Hold mutable mock state so beforeEach can swap the cache root for each test.
-const mockState: { candidates: string[] } = { candidates: [] }
+const mockState: { candidates: string[]; walkUpResult: string | null } = {
+  candidates: [],
+  walkUpResult: null,
+}
 
 mock.module("../constants", () => ({
   INSTALLED_PACKAGE_JSON_CANDIDATES: new Proxy([], {
@@ -22,7 +25,7 @@ mock.module("../constants", () => ({
 }))
 
 mock.module("./package-json-locator", () => ({
-  findPackageJsonUp: () => null,
+  findPackageJsonUp: () => mockState.walkUpResult,
 }))
 
 import { getCachedVersion } from "./cached-version"
@@ -36,11 +39,13 @@ describe("getCachedVersion (GH-3257)", () => {
       join(cacheRoot, "node_modules", "oh-my-opencode", "package.json"),
       join(cacheRoot, "node_modules", "oh-my-openagent", "package.json"),
     ]
+    mockState.walkUpResult = null
   })
 
   afterEach(() => {
     rmSync(cacheRoot, { recursive: true, force: true })
     mockState.candidates = []
+    mockState.walkUpResult = null
   })
 
   it("returns the version when the package is installed under oh-my-opencode", () => {
@@ -77,4 +82,23 @@ describe("getCachedVersion (GH-3257)", () => {
   it("returns null when neither candidate exists and fallbacks find nothing", () => {
     expect(getCachedVersion()).toBeNull()
   })
+
+  it("prefers the loaded module's package.json over flat-install candidates", () => {
+    // OpenCode loads plugins from a per-plugin sandbox at
+    // <CACHE_DIR>/<plugin-entry>/node_modules/<pkg>/, while a parallel flat
+    // install at <CACHE_DIR>/node_modules/<pkg>/ can drift independently when
+    // bun re-resolves "latest". The flat install must NOT take precedence,
+    // because that's the path the user is actually running.
+    const sandboxDir = join(cacheRoot, "oh-my-openagent@latest", "node_modules", "oh-my-openagent")
+    mkdirSync(sandboxDir, { recursive: true })
+    const sandboxPkgJson = join(sandboxDir, "package.json")
+    writeFileSync(sandboxPkgJson, JSON.stringify({ name: "oh-my-openagent", version: "3.17.5" }))
+    mockState.walkUpResult = sandboxPkgJson
+
+    const flatDir = join(cacheRoot, "node_modules", "oh-my-opencode")
+    mkdirSync(flatDir, { recursive: true })
+    writeFileSync(join(flatDir, "package.json"), JSON.stringify({ name: "oh-my-opencode", version: "3.17.6" }))
+
+    expect(getCachedVersion()).toBe("3.17.5")
+  })
 })
diff --git a/src/hooks/auto-update-checker/checker/cached-version.ts b/src/hooks/auto-update-checker/checker/cached-version.ts
index 4cf6ebc1c..59886a17b 100644
--- a/src/hooks/auto-update-checker/checker/cached-version.ts
+++ b/src/hooks/auto-update-checker/checker/cached-version.ts
@@ -13,16 +13,12 @@ function readPackageVersion(packageJsonPath: string): string | null {
 }
 
 export function getCachedVersion(): string | null {
-  for (const candidate of INSTALLED_PACKAGE_JSON_CANDIDATES) {
-    try {
-      if (fs.existsSync(candidate)) {
-        return readPackageVersion(candidate)
-      }
-    } catch {
-      // ignore; try next candidate
-    }
-  }
-
+  // Walk up from the loaded module first. OpenCode loads plugins from a
+  // per-plugin sandbox at <CACHE_DIR>/<plugin-entry>/node_modules/<pkg>/, while
+  // a parallel flat install at <CACHE_DIR>/node_modules/<pkg>/ can drift
+  // independently when bun re-resolves "latest". Reading the flat install
+  // first means the toast can announce a version the runtime isn't running.
+  // The module-relative walk-up always reflects what is actually loaded.
   try {
     const currentDir = path.dirname(fileURLToPath(import.meta.url))
     const pkgPath = findPackageJsonUp(currentDir)
@@ -33,6 +29,16 @@ export function getCachedVersion(): string | null {
     log("[auto-update-checker] Failed to resolve version from current directory:", err)
   }
 
+  for (const candidate of INSTALLED_PACKAGE_JSON_CANDIDATES) {
+    try {
+      if (fs.existsSync(candidate)) {
+        return readPackageVersion(candidate)
+      }
+    } catch {
+      // ignore; try next candidate
+    }
+  }
+
   try {
     const execDir = path.dirname(fs.realpathSync(process.execPath))
     const pkgPath = findPackageJsonUp(execDir)