Sounds a bit weird. The way I did it both times was to start from the first category (Water zone?), do all the possible races in that, then move on to the next category (fire zone?) and do all the possible races on that, then move down to the next zone and so on. Once I finished the last zone I went back up to the first one where an eliminator and speed events were unlocked, along with a couple of races. I did those, moved down to the next zone with newly unlocked events and repeated the cycle.

I can't see any explanation other than you've missed one or more events along the line somewhere.