UI & API: the std. category field is cleared for the Feature on UI but not nulled in the DB.

Issue Summary

Looks like a UI/DB defect: If one of the standard categories (with ids 1-7) is removed from the dropdown - the category field is cleared for the Feature on UI but not cleared in the DB automatically.
On the other hand, if any custom category (with id > 7) is removed from the dropdown - the category field is cleared for the Feature on UI and set to null in the DB automatically.

Steps to Reproduce

see summary

Expected Results

If one of the standard categories (with ids 1-7) is removed from the dropdown - the category field is cleared for the Feature on UI AND set tu NULL in the DB automatically.

Actual Results

If one of the standard categories (with ids 1-7) is removed from the dropdown - the category field is cleared for the Feature on UI but not cleared in the DB automatically.

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available