The vipegconsole.log shows the message "text=SafeRequestProcessorInterceptor destroy() is called..." and then the validation server service on the affected Gateway is stopped.
DEBUG "2017-07-01 02:04:00.957 GMT-0500" 0.0.0.0 UNKNOWN 710767208 0 0 "text=SafeRequestProcessorInterceptor destroy() is called..."
Windows update was found as the reason for services being stopped.