Can you post some example records from vicidial_callbacks and vicidial_list where this problem has happened?
I'll post some examples as soon as it happens again.
crontab -l
### recording mixing for Asterisk
00 18 * * * /usr/share/astguiclient/AST_CRON_mix_recordings_MP3_DATE.pl
### keepalive script for astguiclient processes
* * * * * /usr/share/astguiclient/ADMIN_keepalive_ALL.pl
### kill Hangup script for Asterisk updaters
* * * * * /usr/share/astguiclient/AST_manager_kill_hung_congested.pl
### updater for voicemail
* * * * * /usr/share/astguiclient/AST_vm_update.pl
### updater for conference validator
* * * * * /usr/share/astguiclient/AST_conf_update.pl
### flush queue DB table every hour for entries older than 1 hour
11 * * * * /usr/share/astguiclient/AST_flush_DBqueue.pl -q
### fix the vicidial_agent_log once every hour
33 * * * * /usr/share/astguiclient/AST_cleanup_agent_log.pl
### updater for VICIDIAL hopper
* * * * * /usr/share/astguiclient/AST_VDhopper.pl -q
### adjust the GMT offset for the leads in the vicidial_list table
1 1 * * * /usr/share/astguiclient/ADMIN_adjust_GMTnow_on_leads.pl --debug
### reset several temporary-info tables in the database
2 1 * * * /usr/share/astguiclient/AST_reset_mysql_vars.pl
### optimize the database tables within the asterisk database
3 1 * * * /usr/share/astguiclient/AST_DB_optimize.pl
## adjust time on the server with ntp
30 * * * * /usr/local/bin/ntpdate -u 18.145.0.30 2>/dev/null 1>&2
### VICIDIAL agent time log weekly summary report generation
2 0 * * 0 /usr/share/astguiclient/AST_agent_week.pl
ntpd.conf
restrict default kod nomodify notrap nopeer noquery
restrict 127.0.0.1
server 0.fedora.pool.ntp.org
server 1.fedora.pool.ntp.org
server 2.fedora.pool.ntp.org
server 18.145.0.30
fudge 127.127.1.0 stratum 10
driftfile /var/lib/ntp/drift
keys /etc/ntp/keys