memory leak on duplicately named dnssec-policy

[ant-3044:~/git/bind9] marka% named-checkconf lll
mem.c:667: REQUIRE(isc_refcount_current(&ctx->references) == 0) failed, back trace
0   libisc-9.17.20.dylib                0x00000001006ab618 default_callback + 72
1   libisc-9.17.20.dylib                0x00000001006ab594 isc_assertion_failed + 56
2   libisc-9.17.20.dylib                0x00000001006c4340 isc__mem_destroy + 372
3   named-checkconf                     0x0000000100400548 main + 1460
4   libdyld.dylib                       0x000000018afc9430 start + 4
Abort
[ant-3044:~/git/bind9] marka% cat lll
dnssec-policy x {
};
dnssec-policy x {
};
[ant-3044:~/git/bind9] marka%