The VLS server may reboot itself following internal housekeeping activities. This is not normally a problem, since the VLS saves all state (activations in progress) and restores them on startup.
If the hardware is causing a reboot (e.g. bad power, hardware interrupt error, overheat, etc) or operating system (Linux crash) this too won’t cause a problem since the VLS will automatically recover it’s last known good state.
If you would like Telium to investigate further, please preserve the core dump file so that we can determine the root cause. But in general you can ignore an occasional reboot.