Why Isn't prepareConfigObject() Called In a Job Level BuildConfigurationPlugin?

[Phillip Peterson]

I'm creating an <additionalBuildConfigurationPlugin> (extends BaseBuildConfigurationAwarePlugin implements MiscellaneousPlanConfigurationPlugin).

I have added custom properties to the buildConfiguration in prepareConfigObject().  This works great at the Plan level: prepareConfigObject is called before populateContextForEdit, custom FTL picks up the properties, changes are handled in validate().  No issues there.

However, when viewing the Miscellaneous configuration at the Job level, prepareConfigObject() is never called so my FTL form is empty.

Why is prepareConfigObject() not called at the Job level, or how can I force it?