“Full_ID_of_parent” is not available to use in parameter script. It is a 2d only functionality, to be able to display it in 2d, so it is not a bug, it is the planned functionality. Please check Requests in GDL Manual: https://gdl.graphisoft.com/reference-guide/request-options/
Gergely Fehér
Team Leader, Library Team
GRAPHISOFT SE