Hey Amir,

I'm assuming "unit" means an organisation or a position in this context. No information relating to a deleted org/pos should be kept, it goes through and deletes all reference to the hierarchy before deleteing the hierarchy itself. So tables like pos_assignment and course_completions should have the appropriate columns set to null, and the 'organisation when completed the learning'  column should become empty in your reports.  If you want to keep any of the data I would suggest archiving/hiding the hierarchy rather than deleting it fully from the system, or if you have noticed anywhere that the information is being kept let us know.

Cheers
David