playback wrong after undo

MS 1.1, winxp

am seeing an issue with playback after undo -- anyone else see this same problem?

- start with a measure containing two quarter notes
- change the first quarter note to a half note
- playback the measure and hear one half note
- undo the last edit to restore the two quarter notes
- result: playback the measure again and hear one half note
- expected result: playback should play the two quarter notes