FIX FOR PROBLEM (ish): I have the same problem, however, I am able to resolve it by:
- Clicking on my "rider" sim's relationships folder
- selecting the horse that is stuck in the competition
- selecting "travel" on that horse
- (destination does not matter, select any lot)
- upon loading in, my "rider" sim's task becomes the competition that needs completing.
My sim is able to complete the competition after this along with the reward.
I had two horses that both were stuck in competition, I had to repeat these steps for my other horse.
** Make sure to save your game right after **
Obviously there is still a bug problem, but this was just a work around I found for the time being.
