Horses skill gaining not proceeding

I've played with my horses for a long time, and recently a lot of bugs have occured due to their skill building. Whenever I try to make my sim practise the bar never pops over to the next level, it only continues on the current one. For example one of my horses completed "235 percent" of level 9, without reaching level 10. This led to me being forced to manually cheat to the next level