Can't re-unlock Shadow Dancing because I have all 24 time trial staff ghosts

[MotleyPriest111]

My achievement tracker glitched the other night, and the only one I can't re-unlock is Shadow Dancing (defeat a staff ghost on one time trial course) because I already unlocked Ghost Master (defeat a staff ghost on every time trial course). The staff ghosts are replaced with the impossible Sumo ghosts. I've tried playing offline (someone in another topic suggested this) and I really don't think starting from scratch is going to fix this since the glitch will just happen again. Any ideas on how to reset the time trials only or something?

[fillebeerke]

i beat the Sumo ghost on the track i think i was missing.... and still no achievement :(
i raced every time trail and still it says 23/24