[3.0.2.0-32] Agent crash @ LifetimeActor::DependencyAdd

Observed the crash while deleting scale config ( lif and vmi and VN) across project in parallel.

Backtrace
-----------------
(gdb) bt
#0 0x00007f524ff05cc9 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1 0x00007f524ff090d8 in __GI_abort () at abort.c:89
#2 0x00007f524fefeb86 in __assert_fail_base (fmt=0x7f525004f830 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n",
    assertion=assertion@entry=0x11a753f "!deleted_", file=file@entry=0x12d1b88 "controller/src/base/lifetime.cc",
    line=line@entry=129,
    function=function@entry=0x12d23c0 "void LifetimeActor::DependencyAdd(DependencyRef<LifetimeRefBase, LifetimeActor>*)")
    at assert.c:92
#3 0x00007f524fefec32 in __GI___assert_fail (assertion=0x11a753f "!deleted_",
    file=0x12d1b88 "controller/src/base/lifetime.cc", line=129,
    function=0x12d23c0 "void LifetimeActor::DependencyAdd(DependencyRef<LifetimeRefBase, LifetimeActor>*)") at assert.c:101
#4 0x000000000117b5ff in LifetimeRefBase::LifetimeRefBase(LifetimeActor*) ()
#5 0x0000000000b0996e in Icmpv6Proto::CreateAndSetVrfState(VrfEntry*) ()
#6 0x0000000000b09e8b in Icmpv6Proto::VrfNotify(DBTablePartBase*, DBEntryBase*) ()
#7 0x000000000107dd3a in DBTableBase::RunNotify(DBTablePartBase*, DBEntryBase*) ()
#8 0x0000000001080428 in DBTablePartBase::RunNotify() ()
#9 0x000000000107c530 in DBPartition::QueueRunner::Run() ()
#10 0x000000000118d89c in TaskImpl::execute() ()
#11 0x00007f5250ad4b3a in ?? () from /usr/lib/libtbb.so.2
#12 0x00007f5250ad0816 in ?? () from /usr/lib/libtbb.so.2
#13 0x00007f5250acff4b in ?? () from /usr/lib/libtbb.so.2
#14 0x00007f5250acc0ff in ?? () from /usr/lib/libtbb.so.2
#15 0x00007f5250acc2f9 in ?? () from /usr/lib/libtbb.so.2
#16 0x00007f5250cf0182 in start_thread (arg=0x7f523bfff700) at pthread_create.c:312
#17 0x00007f524ffc947d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

root@5b7s6:~# contrail-version | grep vrouter
contrail-vrouter-3.13.0-40-generic 3.0.2.0-32 32
contrail-vrouter-agent 3.0.2.0-32 32
contrail-vrouter-common 3.0.2.0-32 32
contrail-vrouter-init 3.0.2.0-32 32
contrail-vrouter-utils 3.0.2.0-32 32
python-contrail-vrouter-api 3.0.2.0-32 32
python-opencontrail-vrouter-netns 3.0.2.0-32 32