Sims freeplay baby steps update - Baby won't keep playing the xylophone

I completed the baby steps quest, and I'm now working on the hobby.  But the baby won't keep playing the xylophone.  I'll start him playing it, exit out of the game, when I go back into the game, the baby is in his crib again.  He played it once, and got the 1st prize, but that's it.  What do I do?  This is a timed hobby.