NTP segfault when using CA signed certificate on RHEL6

Issue

When trying to authenticate NTP (PKI based )with a CA signed certificate results in the following error:

kernel:ntpd[11589]: segfault at 0 ip 00007fb9a75c0566 sp 00007ffc8ed67868 error 4 in libc-2.12.so[7fb9a7498000+18a000]

ntp.conf has been configured as follows:

crypto randfile /dev/urandom
includefile /etc/ntp/crypto/pw
keysdir /etc/ntp/

Autokey is configured for the NTP server.

The following errors are seen intermittently

20 Dec 16:48:46 ntpd[5249]: cert_parse: invalid certificate ccm203 first 3691215179 last 3722751779 fstamp 3691215987
20 Dec 16:48:46 ntpd[5249]: certificate file ntpkey_cert_ccm203 not found or corrupt
20 Dec 16:57:57 ntpd[5503]: crypto_key: no filestamp /etc/ntp//ntpkey_host_ccm203

NTP authentication succeeds with NTP certificates and openssl self signed certificates.