[bug] undefined is not an object (evaluating '[callbackId, data]')

[deJong-IT]

Describe the bug

We’re seeing the same error on iOS when requesting location permissions:
undefined is not an object (evaluating '[callbackId, data]')

It looks related to issue #13907

It looks like the issue comes from the then following the catch.
Since the catch block doesn’t return anything, the then handler always receives undefined, which causes this error.

Relevant code:

tauri/crates/tauri/scripts/ipc-protocol.js

Lines 55 to 67 in 67c7418

	.catch((e) => {
	console.warn(
	'IPC custom protocol failed, Tauri will now use the postMessage interface instead',
	e
	)
	// failed to use the custom protocol IPC (either the webview blocked a custom protocol or it was a CSP error)
	// so we need to fallback to the postMessage interface
	customProtocolIpcFailed = true
	sendIpcMessage(message)
	})
	.then(([callbackId, data]) => {
	window.__TAURI_INTERNALS__.runCallback(callbackId, data)
	})

Reproduction

No response

Expected behavior

No response

Full tauri info output

[✔] Environment
    - OS: Mac OS 15.7.1 arm64 (X64)
    ✔ Xcode Command Line Tools: installed
    ✔ rustc: 1.88.0 (6b00bc388 2025-06-23)
    ✔ cargo: 1.88.0 (873a06493 2025-05-10)
    ✔ rustup: 1.28.2 (e4f3ad6f8 2025-04-28)
    ✔ Rust toolchain: stable-aarch64-apple-darwin (default)
    - node: 23.6.0
    - npm: 10.9.2

[-] Packages
    - tauri 🦀: 2.8.5, (outdated, latest: 2.9.1)
    - tauri-build 🦀: 2.4.1, (outdated, latest: 2.5.1)
    - wry 🦀: 0.53.3, (outdated, latest: 0.53.5)
    - tao 🦀: 0.34.3, (outdated, latest: 0.34.5)
    - @tauri-apps/api : not installed!
    - @tauri-apps/cli : 2.7.1 (outdated, latest: 2.9.1)

[-] Plugins
    - tauri-plugin-os 🦀: 2.3.1
    - @tauri-apps/plugin-os : 2.3.0 (outdated, latest: 2.3.1)
    - tauri-plugin-log 🦀: 2.6.0, (outdated, latest: 2.7.0)
    - @tauri-apps/plugin-log : not installed!
    - tauri-plugin-geolocation 🦀: 2.3.0
    - @tauri-apps/plugin-geolocation : 2.3.0
    - tauri-plugin-haptics 🦀: 2.3.0
    - @tauri-apps/plugin-haptics : 2.3.0

[-] App
    - build-type: bundle
    - CSP: unset
    - frontendDist: ../build
    - framework: React
    - bundler: Rollup

Stack trace

Additional context

We are going to update to the latest tauri versions, but in the code, the issue still exists, so we do not expect it to be solved