My child can't acquire the Piano skill

[oshizu]

When a child is an Artistic Prodigy in my games, they always save the "Play a music instrument for 5 hours" for last.

Once they've maxed Creativity, they will acquire the skill and gain levels in the musical instrument they're playing.
They usually complete Artistic Prodigy with 4-5 levels in that musical instrument if they were constantly Encouraged while drawing.

This happens roughly 90% of the time, but occasionally a child can't acquire a musical instrument skill.
I've even had a case where one child acquired the Violin skill but his twin brother could acquire neither the Violin or Piano skill until he reached teenhood.

Does this happen to anyone else? Is there a workaround?
Thanks for reading.

[Playalot]

I've also had this happen but as I was rushing to complete the aspiration I basically ignored it and decided it was just a glitch in my game and carried on without actually investigating!

Have you cleared caches etc? I'm kind of curious now that someone else has had this happen.

[oshizu]

I'm playing a different household in a rotational challenge, but I'll be returning to those twins next week or so.
Thank you for suggesting that I clear caches. I'll be sure to do that and try again, since the twins will still be children next week.

I'll let you know how that goes.