https://qa.debian.org/bls/packages/m/monitoring-plugins.html indicates that check_ntp had a sloppy commit in the recent past:
pointer-from-integer check_ntp.c:619 - https://github.com/monitoring-plugins/monitoring-plugins/blob/master/plugins/check_ntp.c#L619 This commes with https://github.com/monitoring-plugins/monitoring-plugins/commit/a04df3e1b67dc5eab3adc202cc89901f801cdeaa -- Reply to this email on GitHub: https://github.com/monitoring-plugins/monitoring-plugins/issues/1285