When I use a "Insta Warp with blackout"- or a "Instawarp with zapeffects"-warptype to warp Link to the same dmap, the music restarts sometimes and sometimes not. I don't know, on wich this depends on. But I read at ZCwiki that the "Entrance/Exit"-warptype is the ONLY warptype that restarts the music (after warping to the same dmap). So I think, this is a bug.
(sorry for my bad english)