How do I get the value of a built in field called "Flag1" when it isn't showing up in the http requests for returning task fields?

[Mgodby]

Hello. I am trying to get the value of a built in task field called "Flag1" from project online. I renamed it as "Report? Y/N" in the view.

I have this action that gets information from the built in field "Flag1", but it doesn't return the value.  

It returns the same as if the field didn't exist at all:


And when I run this http request which lists out all the task fields, including some custom fields, Flag1 doesn't show up.

Is there a way to get the value of this task field? I am able to access custom fields and other built in fields but not this one. 

Thank you.