I don't know whether it's a bug or a feature which isn't implemented completely yet, but it seems to me that on some tracks you'll get certain bonuses more often than others / than on other tracks.
For example: On "Fort Magma" I'm getting in nearly 9 of 10 cases one of those ugly chewing gums and nothing else, while Ice Track or Tux Tollway are presenting many, many parachutes (especially to the AIs )
This is a bit annoying: Fort Magma isn't very interesting (the AIs are always half a round behind me) while tracks like Tux Tollway are quite hard - everywhere these parachutes and anchors. Is this a kart racing or a kart stopping game? :P
Crendgrim