Why aren't these colors the same?

When I run:
proc format ;
  value $sub
    "bibbity" = "5"
    "bobbity" = "30"
    "boo" = "80"
    "baz" = "120"
    "foo" = "150"
    "zoob" = "180"
  ;
quit ;

data test ;
  do subject = 'bibbity', 'bobbity', 'boo', 'baz', 'foo' ;
    do obs_date = '01-jan-2010'd to '31-dec-2013'd by 30 ;
      num_widgets = input(put(subject, $sub.), best.) + floor(uniform(4) * 30) ;
      proportion_blue = uniform(4) ;
      output ;
    end ;
  end ;
  format obs_date mmddyy10. proportion_blue percent9.2 ;
run ;

%let out_folder = c:/temp/ ;

ods graphics / height = 6in width = 10in ;
ods html path = "&out_folder" (URL=NONE)
         body   = "deleteme.html"
         (title = "Why are bubble color and line color not coordinated?")
          ;

  proc sgplot data = test ;
    loess  x = obs_date y = num_widgets / group = subject ;
    bubble x = obs_date y = num_widgets size = proportion_blue / group = subject transparency=0.5 ;
    xaxis grid ;
    yaxis grid ;
  run ;

ods _all_ close ;

I get:

I think it's confusing that the bubble colors and the loess line colors don't match.

If I change from loess to a series plot, the colors match.

Anybody know how I can get the colors to match?

Thanks!