Guest OS: Ubuntu 16.04.4 LTS (kernel versions 4.4.0-108 to current 116)
Virtualization env: VMWare ESXi 6.0
Host hardware: Dell R720
Using SSSD to bind linux servers to the AD domain for authentication. This was working fine right up to 4.4.0-104. After the update to -108,-109,-112, or -116, if sssd is enabled OR if it is disabled but then started after a successful boot and you perform a lookup (i.e. id some_domain_user), the entire system will freeze, and you have to force a reboot. There's even a blip in the syslog when it happens.