The sex of the kits if determined by the buck shortly after conception.
Having a litter of all bucks does not mean the doe would be predisposed to only having bucks or that another litter would only have does. A buck could be more prone to producing one sex though, but I doubt it would be that common.
Also remember that any change of sexes are for each kit, not for a litter as a whole. So each kit would have a 50% chance of being male and 50% of being female. Each kit in a litter could end up being bucks, just like you could toss a coin and have it land heads up 5 times in a row.