To reproduce this do:
1. drush dl panopoly
2. Download translation package .po (in my case Finnish) in /profiles/panopoly/translations
3. Create a database
4. Go to the project url -> installing starts
5. Choose Panopoly as your installation profile
6. Installation skips 'Choose language' and 'Verify requirements' and stops to 'Set up database' stage
Installing the standard profile works correctly. I tried to check the issue with debugger. With Panopoly profile it didn't run the function install_select_locale in install.core.inc. I couldn't find the reason why. I'm not familiar with the installation process.