Recoed Attack doesn't like external sprites?

So while I was messing with an unofficial riders mod that no one wants, I was thinking of recording replays... until I may have realized a very weird bug with record attack.

Any custom sprites used on a character or any characters count as unknown in record attack.... This may be because SRB2's gamedata doesn't recognize these custom sprites. The weird thing is... the wads are added alongside the main wad and are used at the same time when recording, and replaying, but not when rerecorded as Ghosts.... how come?