Steps to reproduce:

1. Use a translated language (french in my case but I guess the issue exists for all tranlated languages)
2. Navigate to a map  which has an element with some url defined
3. Click on that element 

Result:
See screenshot : popup URL section title is "LINKS"
Expected:
It should be "LIENS" instead (as defined in frontend.po/mo)

Workaround:
edit jsLoader.php and add :

'Links' => _('Links'),

 in menupopup.js array