makepkg --syncdeps ignores dependencies which are defined in the package function of a split package such like this:

package_python-django-djblets() {
depends=('python-django>=1.6.7' 'python-django<1.7' 'python-feedparser' 'python-pytz'
'python-pillow' 'python-django-pipeline' 'nodejs-uglify-js')
makedepends=('python-setuptools' 'lessc')

cd "${srcdir}/${_pkgname}-release-${pkgver}"
python setup.py install --prefix=/usr --root="${pkgdir}" --optimize=1
}

package_python2-django-djblets() {
depends=('python2-django>=1.6.7' 'python2-django<1.7' 'python2-feedparser' 'python2-pytz'
'python2-pillow' 'python2-django-pipeline' 'nodejs-uglify-js')
makedepends=('python2-setuptools' 'lessc')

cd "${srcdir}/${_pkgname}-release-${pkgver}"
python2 setup.py install --prefix=/usr --root="${pkgdir}" --optimize=1
}

If I put the depends arrays outside of the package functions --syncdeps works. The version restriction inside the package function is ignored as well.