z/OS MF file space had run out and I was getting failures (but these weren't all reported by the Endevor action event processing).
Actually, when z/OS MF file space ran out of memory, it created the Endevor event files with a tempname:
The reason that webhook didn't report the consumption or report of these elements is that the system looks for files with a specific naming convention.
The files to be consumed by webhook server must have at least an application type (ELM or PKG) and an action type (ADD, UPDATE)... Consequentially, these elements were "ignored" by webhook server.
However, if the other elements were not consumed by webhook server in this specific scenario, then we have a defect to resolve: