Post Install Redirect for apps, has something changed?

[emma_patterson]

In my appDescriptor I have set up a postInstallRedirect like so:

modules: {
    postInstallRedirect: {
        key: 'redirect',
        url: `https://bitbucket.org/{user_username}/workspace/settings/addon/admin/${appKey}/repository-settings?post-install=true`
    }

This used to work perfectly but recently something has gone wrong and now after installing I see the page as follows:

Can someone help explain how this could have happened? 
I see no change logged in this area from Bitbucket?

Thanks in advance,
Emma