Sorter (ldns) segfault with WKS RR

In my unsigned zone:
IN WKS 128.32.0.10 UDP who route timed domain

Result from GDB:

Starting program: /usr/local/libexec/opendnssec/sorter -o all.rr.org -f /home/rickard/opendnssec/unsigned/all.rr.org -w /home/rickard/opendnssec/tmp/all.rr.org.sorted -m 60

Program received signal SIGSEGV, Segmentation fault.
0xb7db649d in ldns_set_bit (byte=0x0, bit_nr=7, value=true) at util.c:112
112 *byte = *byte | (0x01 << bit_nr);
(gdb) bt
#0 0xb7db649d in ldns_set_bit (byte=0x0, bit_nr=7, value=true) at util.c:112
#1 0xb7dc2290 in ldns_str2rdf_wks (rd=0xbffa1d6c, str=0x805e838 "UDP who route timed domain") at str2host.c:973
#2 0xb7db576d in ldns_rdf_new_frm_str (type=LDNS_RDF_TYPE_WKS, str=0x805e838 "UDP who route timed domain") at rdata.c:310
#3 0xb7db96ce in ldns_rr_new_frm_str_internal (newrr=0xbffa1ec0, str=<value optimized out>, default_ttl=60, origin=0x804c308,
prev=0xbffa1ebc, question=false) at rr.c:486
#4 0x08049755 in main (argc=-1074127160, argv=0x805cae0) at ../../../signer/tools/sorter.c:455