For a recipe with LICENSE containing multiple licenses and then individual packages having their own LICENSE_ settings, the license information in the RPM for ${PN} is ${LICENSE}, not ${LICENSE_${PN}} as it should be. It works correctly for all other packages.

To reproduce:

1) Create "recipes-support/licensetest/licensetest_1.0.bb":

LICENSE = "GPL-3.0 & LGPL-2.1"
LIC_FILES_CHKSUM = "file://${COREBASE}/meta/files/common-licenses/GPL-3.0;md5=c79ff39f19dfec6d293b95dea7b07891 \
                    file://${COREBASE}/meta/files/common-licenses/LGPL-2.1;md5=1a6d268fd218675ffea8be556788b780"

inherit allarch

do_install() {
    mkdir -p ${D}${bindir} ${D}${libdir}
    touch ${D}${bindir}/licensetest
    touch ${D}${libdir}/licensetest.so.1.0.0
}


PACKAGE_BEFORE_PN += "${PN}-libs"

LICENSE_${PN} = "GPL-3.0"
LICENSE_${PN}-dbg = "GPL-3.0"
LICENSE_${PN}-dev = "GPL-3.0"
LICENSE_${PN}-libs = "LGPL-2.1"

FILES_${PN}-libs = "${libdir}"

2) Make sure package_rpm is included in PACKAGE_CLASSES, e.g. by adding 

PACKAGE_CLASSES += "package_rpm"

to "conf/local.conf".

3) Build licensetest: 

bitbake licensetest

4) Extract license information from the built packages:

rpm -qilp tmp/deploy/rpm/*/licensetest*|grep 'Name\|License'

This gives:

Name        : licensetest
License     : GPL-3.0 & LGPL-2.1
Name        : licensetest-dbg
License     : GPL-3.0
Name        : licensetest-dev
License     : GPL-3.0
Name        : licensetest-libs
License     : LGPL-2.1

and as can be seen, the licenses are correct for licensetest-dbg, licensetest-dev and licensetest-libs, but wrong for licensetest.