Objects do not have threads to burn backward. No matter how strong Rand's balefire, it would not have affected the history of the manor. If you want to find a valid counter argument for the compulsion being removed other than Graendal dying, you'd have better luck pretending that balefiring the doorman that let the messenger into the manor prevented the messenger from ever being allowed into the manor and so he was never compelled. It's farfetched but more plausible than history being affected by a physical object being balefired.