Discarding Light tokens after slumber?

Hi,

So I played the wraith slumber and chased it away. During play I placed one terrain light token to defeat the wraith on that specific tile. Placing a light token is one of the abilities on the wraith entity tile.

Rule says after slumber ends do [u][b]not[/b][/u] discard tokens that are not associated to the slumber tile. Is the light token associated to the slumber entitiy tile or is it a more general token? In other words do I need to discard the light token or not?

Thanks

Rikkert