I noticed the Bug first on 12/18 with the Actor Career from the Get Famous Expansion.
It might be important to note that except for the Vampire Expansion - I have all the EA Packs, Content, and Expansions.
I first noticed this on a Saved game and then have been testing it out on completely randomized and brand new game Sims. No Mods or CC.
What happens is - After choosing the Actor Career, the Talent agency, and the First gig - which is the music player. I buy a guitar and start to practice.
The skill increases and reaches level two as expected, the bubble pops and it says that I skilled up over the Sim.
The Bug is that the career progression tab where it shows the need to increase the guitar skill and the game scripting itself does NOT mark the guitar skill as having increased.
Then the first gig the sim plays fails because the skill did not register as increasing to level two.
I have done the following things in testing the bug and started fresh games each time without CC or Mods.
Followed the Forum steps to delete Cache files and the SIMS4 files relating to the Get Famous Expansion
1a. Reinstalled Get Famous expansion and repaired Game Files.
Retested and confirmed bug exists.
2. Uninstalled the game through Windows and then deleted remaining game files.
2a. Reinstalled the entire game through Origin. Updated Game
Retested and confirmed bug exists.
3. Logged in on another PC today 12/21 - Updated latest files through Origin. Retested - Confirmed Bug