A policy was somehow was saved in an invalid state. According to XML validator, it appears to be valid. However the gateway to be unable to execute it.
This is due to the mismatch id between the gateway loaded service and the service in database. This is generally due to a migration issue.
Nine times out of ten an "invalid service goid" should be due to the mismatch id between the gateway loaded service and the service in database. Restarting ssg (sometimes server reboot is needed) should reload the service from database and resolve this problem .
You may need to completely remove the policy and install it again if the reboot does not work.
The other time out of ten it may be due to an improperly configured XSL transformations, in the Apply XSL Transformation assertion, there is an xsi:schemaLocation attribute. The XSL processor in the gateway does not support it. After removing the attribute, the policy should process fine.
Apply XSL Transformation assertion: https://community.broadcom.com/communities/community-home/digestviewer/viewthread?MID=754705#bm649454e7-b542-4afc-8147-386a43d9814f