Strange behavior with stereo panning in hsc3-0.9

gistfile1.hs

import Control.Exception
import qualified Sound.SC3 as SC

-- Haskell version
incorrectPan = withSuperCollider $ do
        SC.audition $ SC.out 0 $
            0.2* SC.balance2 (osc 220) (osc 220) mod (SC.constant 1)
        getChar
    where
    osc freq = SC.sinOsc SC.AR (SC.constant freq) (SC.constant 0)
    mod = SC.sinOsc SC.KR (SC.constant 0.2) (SC.constant 0)
    withSuperCollider = bracket_
        (SC.withSC3 $ \fd -> SC.send fd (SC.g_new [(1, SC.AddToTail, 0)]))
        (SC.withSC3 $ \fd -> SC.send fd (SC.n_free [1]))

-- Presumably equivalent SuperCollider code
{-

(
SynthDef.new("test-balance", {
    Out.ar(0,
        0.2 * Balance2.ar(SinOsc.ar(220,0), SinOsc.ar(220,0), SinOsc.kr(0.2,0))
    ) }).play;
)

-}