Hi, i think there is a known issue about failing reboot, i think there is a specific patch.
Is your installation 9.6 sp2, or you have also added some extra patches?
My installation is 9.6 SP 2 with additional two patches.
i recommend you to open a ticket and specify exactly the patches installed after sp2,
As an example, consider that in my production environment i have installed 9.6 sp2 and the patches listed below:
the support team will provide you the links for the patches that will address your issue