Career Development: is it possible to add development goals to non-primary assignments?

Summary

We need to add development goals on the non-primary assignment

Content

We need to add development goals on the non-primary assignment.

Scenario

1. the employee has multiple assignments with different line managers
2. the 'Setup of Development Goals Mass Assignment' feature allows to select the non-primary assignment of the employee
3. the 'Scheduled Processes for Development Goals' process does not add Goals to the employee

Is this a bug or is the functionality not supported?

Moreover: it seems that the employee through the UI can only add development goals on the primary assignment, correct? 

Thanks,
Patrizia