[referrer] Should referrer policy change value of the Origin header?

I note that most recent Chrome will change the value of the Origin header
on, e.g. a same-origin POST to "null" if there is a meta-referrer policy of
'never' or 'no-referrer'.

Should it do this?  Seems possibly logical, but there is no mention of this
in the spec...

(Firefox, to my continuing sadness, doesn't send Origin on POST at all.)

-Brad