Won't give Master Pianist challenge credit

[Crounsaville]

Two of my 5 sims  have purchased and learned 100% of the piano tracks but the game is  only showing credit for 86% of one sim and 55% of the other.   I have re-purchased all of the tracks a second time hoping that there might be something that I have missed, but I have confirmed that all 100% of the tracks are available in their playlists,  and it will not allow me to relearn a track that has already been learned. Any ideas on how to fix this glitch?

[MrsFlynn]

You might try resetting the Sims involved or evicting them as away of resetting them. Also deleting game cache might help also.

Reset Town, Individual Sims and/or Evict Household (How-To)
http://www.carls-sims-4-guide.com/forum/index.php?topic=20732.msg401812#msg401812

Delete Game Cache Files (What & Howto)
http://www.carls-sims-4-guide.com/forum/index.php?topic=20732.msg401809#msg401809