Products/Five/i18n.zcml uses namespace package in configure package directive
when using eggified zope.* packages in Zope2 (i.e. for use with singing-dancing or z3c.forms) zope. and zope.app. are namespace packages.
Five uses in its i18n.zcml http://
which is wrong: zope.app as a namespace has several location. the directory locales cant be found in every case (it maybe found randomly).
solution is to use the full package name zope.app.locales and as directory just a dot:
this will work in all cases.