`_changeProperties` can't set an Optional value to empty

(Bug, Closed -> Fixed, Priority: Critical, Test Status: No automated tests yet , Reported By Bad Link: Thing 3y284oe not found, )
Functions
Summary: For example, if you have a Property named Optional Number, and try to set that as _changeProperties(Optional Number(< >)), you get the error Optional Number parameter 0 should be of type Whole Number Type but is actually Unknown Type.