(In reply to Kohei Yoshino [:kohei] (Bugzilla UX) (FxSiteCompat) from comment #0)
Somehow nobody has filed or noticed this bug, but as :marco pointed out on IRC, the current
/rest/bug API doesn’t return inactive custom fields like
cf_status_firefox33 even if it’s set. Maybe we could add a new filter like
include_fields=custom_all that returns all the fields including old ones.
That'd be include_fields=_custom_all, which (in the active_custom_fields hook)