I've got answer from Qlik
"This is by design; users will not be able to export data from apps that has been shared by others.
This is designed to protect the apps from being modified by the users you share with.
Anything that is in the Shared stream cannot be downloaded by anyone. However, for apps that you own/created, you can move them to your personal stream and download them, if needed.
The ability to have others download or modify apps is on our roadmap of offerings. This will be made available in our future releases."