That's nothing to do with the build. That's a material that doesn't have a definition and therefore has 0 grip, in a spot you wouldn't normally be expected to get to. An oversight, sure, but it's pretty minor. The fix, if they bother, would be in a future version of the track.
@Driver_rF2 Your material names need to be referenced properly in the .tdf. You should ask about this sort of thing in the modding forum, as it's not a bug.
