Run following command and check if it works for you.
chkconfig ipaliases on
You may also want to check log message just after reboot and IP is not added in WHM.
tail -100 /var/log/messages
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I work more with WHM on a virtualized level, but I believe on WHM Accelerated installs the I.P. should be present in /etc/ips if not, you may have to go through and remove/re-add process. There may be a /scripts if you want to try adding it from the CLI. You'd want to run it through Google to determine which one.
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