[GRO] Milestones stop accomplishing when leaving lot

It only happened once as far as I could tell, since I stopped counting the fact that even after the graduation ceremony my sims don't have that milestone. It was a child sim. He learnt how to ride a bike twice without the milestone activating, the third time even the learning choice was gone, he could only ride the bike, which is not surprising if you take into consideration that he had already mastered that skill twice. I just aged him up without that particular milestone. Felt bad though, as if he had missed on an important life experience.