I purchased (lifetime) the iOS app using my Apple ID which is registered as a Apple ID family account today. The link to the Mac App on my Mac using my email address works smooth. I expected that the iOS version can be used to the same vault on another family member Apple ID iPhone. Long story short: I purchased the iOS app on one family device and expected that the iOS app is also included in the lifetime license as it is a family sharing app.
However, when I loaded the app on my wife's iPhone, the app did not seem to be also unlimited? How to change that?