In T12321#213543, @epriestley wrote:

This does not describe a bug in Phabricator. I've reviewed the documentation and believe it is already sufficiently clear in describing how to accomplish what you're trying to accomplish. Particularly, I don't see anything in the documentation which is misleading, or suggests that the workflow you're using is the correct way to accomplish your goal -- it isn't, and the documentation describes the correct workflow. See Support Resources for other support resources.

From what I understood, if I edit the built-in form, It would apply globally, so I only wanted that field hidden, if it was a new form. which is what I was trying to create.

I am not able to edit the form such that users belonging to a certain group are not able to change the state ie: "close" a task.
Having read into other similar situations ( T11207 ) and reading that your solution is to use custom forms I began investigating custom forms.

commit eec6cd865c854fd00c8de41b8ca8ed0da78760e8
Author: Chad Little <chad@phacility.com>
Date: Fri Feb 24 15:21:23 2017 -0800