radvd advertises on wrong intereface

Running radvd 1:1.9.1-1.1ubuntu2 on Ubuntu 14.4 LTS amd64 with the following config:

interface eth0
{
 AdvSendAdvert on;
 UnicastOnly on;
 prefix 0:0:0:e0::/64
 {
  AdvOnLink on;
  AdvAutonomous on;
  AdvRouterAddr on;
  Base6to4Interface ppp0;
 };
};

interface ethc6
{
 AdvSendAdvert on;
 UnicastOnly on;
 prefix 0:0:0:e1::/64
 {
  AdvOnLink on;
  AdvAutonomous on;
  AdvRouterAddr on;
  Base6to4Interface ppp0;
 };
};

IPv6 is provided via 6to4 off ppp0 public IP. If both interfaces are enabled, eth0 IPv6 advertisements are seen on eth1 network. forwarding is enabled for ipv6. This causes clients to get both e0 and e1 flavor addresses. They choose the e0 flavor while on eth1 network and no ipv6 networks can be reached.

disabling radvd config for eth0 causes eth1 systems to get connectivity, but then no eth0 connected hosts have connectivity.

== ApportVersion =================================
2.14.1-0ubuntu3.10

== Architecture =================================
amd64

== Date =================================
Thu Apr 30 23:34:08 2015

== Dependencies =================================
adduser 3.113+nmu3ubuntu3
apt-utils 1.0.1ubuntu2.7
debconf 1.5.51ubuntu2
debconf-i18n 1.5.51ubuntu2
debianutils 4.4
dpkg 1.17.5ubuntu5.4
gcc-4.8-base 4.8.2-19ubuntu1
gcc-4.9-base 4.9.1-0ubuntu1
libacl1 2.2.52-1
libapt-inst1.5 1.0.1ubuntu2.7
libapt-pkg4.12 1.0.1ubuntu2.7
libattr1 1:2.4.47-1ubuntu1
libaudit-common 1:2.3.2-2ubuntu1
libaudit1 1:2.3.2-2ubuntu1
libbz2-1.0 1.0.6-5
libc6 2.19-0ubuntu6.6
libdaemon0 0.14-2ubuntu1
libdb5.3 5.3.28-3ubuntu3
libgcc1 1:4.9.1-0ubuntu1
liblocale-gettext-perl 1.05-7build3
liblzma5 5.1.1alpha+20120614-2ubuntu2
libpam-modules 1.1.8-1ubuntu2
libpam-modules-bin 1.1.8-1ubuntu2
libpam0g 1.1.8-1ubuntu2
libpcre3 1:8.31-2ubuntu2
libselinux1 2.2.2-1ubuntu0.1
libsemanage-common 2.2-1
libsemanage1 2.2-1
libsepol1 2.2-1ubuntu0.1
libstdc++6 4.8.2-19ubuntu1
libtext-charwidth-perl 0.04-7build3
libtext-iconv-perl 1.7-5build2
libtext-wrapi18n-perl 0.06-7
libustr-1.0-1 1.0.4-3ubuntu2
multiarch-support 2.19-0ubuntu6.6
passwd 1:4.1.5.1-1ubuntu9
perl-base 5.18.2-2ubuntu1
sensible-utils 0.0.9
tar 1.27.1-1
zlib1g 1:1.2.8.dfsg-1ubuntu1

== DistroRelease =================================
Ubuntu 14.04

== NonfreeKernelModules =================================
nvidia

== Package =================================
radvd 1:1.9.1-1.1ubuntu2

== PackageArchitecture =================================
amd64

== ProblemType =================================
Bug

== ProcEnviron =================================
TERM=screen
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_US.UTF-8
SHELL=/bin/bash

== ProcVersionSignature =================================
Ubuntu 3.13.0-49.83-generic 3.13.11-ckt17

== SourcePackage =================================
radvd

== Tags =================================
 trusty

== Uname =================================
Linux 3.13.0-49-generic x86_64

== UpgradeStatus =================================
Upgraded to trusty on 2014-05-11 (354 days ago)