False positive on Time.days_in_month inside Range.new

[Fustrate]

I'm getting the following false positive:

Do not use Time.new without zone. Use one of Time.zone.local, Time.current, Time.new.in_time_zone, Time.new.utc, Time.new.getlocal, Time.new.iso8601, Time.new.jisx0301, Time.new.rfc3339, Time.new.to_i, Time.new.to_f instead.

on this code:

def make_calendar_hash(date)
  Range.new(1, Time.days_in_month(date.month, date.year)).map do |day| # <-- Here
    {
      date:   Time.zone.local(date.year, date.month, day),
      events: []
    }
  end
end

Strangely, it goes away when I move the method out of Range.new:

def make_calendar_hash(date)
  days_in_month = Time.days_in_month(date.month, date.year)

  Range.new(1, days_in_month).map do |day|
    {
      date:   Time.zone.local(date.year, date.month, day),
      events: []
    }
  end
end

days_in_month is a class method that only exists on Time as far as I can tell, although I think it has more to do with it being inside another method call than being a false positive unto itself.

---

$ rubocop -V
0.42.0 (using Parser 2.3.1.2, running on ruby 2.3.1 x86_64-darwin15)

I tested with both the published version (0.42.0) and built from master at 19b7035