Task type change not reflected after calling updateTask

This is reproducible only in the opensource version (4.0.0)

The snippet shows the expected result (docs.dhtmlx.com/gantt/snippet/db4d4dfd), however using the opensource version the rendered task type remains unchanged.

unfortunately, project types are supported only in commercial editions.
You can emulate them in gpl version by adding some flag to those items in order to color them appropriately, and either manually calculating project dates or setting start_date/end_date of those items to null (this was a non-documented way to emulate project behavior where projects are not supported)