A recently discovered bug in Android 16 allows any app to leak traffic outside the VPN tunnel.

The bug was reported to the Android Security Team, but was closed as Won’t Fix (Infeasible) [...] In contrast, GrapheneOS, a security-focused Android-based OS, quickly patched the issue in its codebase.

A mitigation is possible, but is quite technical in that it requires USB debugging to be enabled on the device in order to run the following Android Debug Bridge (adb) commands:

adb shell device_config put tethering close_quic_connection -1

adb reboot