What is this unknown Google-originating client that triggers JavaScript errors in our PWA?
This might be a headless Chrome (probably pre-release tests, in case you have it in the Play Store), which does not feature push permission; eg. with Pupeteer, one can only override permissions, but not really accept the permission prompt... and there generally is no desktop attached, where one could push notifications to.
Just try and catch to sort out clients not supporting push permission.
navigator.permissions .query({name: 'push', userVisibleOnly: true}) .then(function(permissionStatus) { console.log('push permission state is ', permissionStatus.state); }) .catch((error) => { console.warn(error); });