I also don't think you caused the martial arts outfit problems, Joolander, as I am having the problems and I'm running a vanilla game and didn't even know about that cheat. 

I am also having the problem with the known songs.  My sims learned both songs while in China and they both appeared in the list fine while in China, and when they returned home the friendly song title was duplicated for the romantic song.  The same is happening for my sim who went to Egypt and learned both songs there, but when I noticed it was soon after moving the family to a fresh neighborhood and I thought that had something to do with it.  The known song menus get messed up during the return home process.

I'm no longer able to have fun playing Sims 3 with all the bugs and hassles, so I have only been playing with CAW for the past few weeks.

I wanted to update about the weirdness I've experienced with the martial arts outfits.  In Sunset Valley, father (adult) and son (teen) both changed their hair styles when switching to the martial arts outfit.  I sent them and the grandfather to China for a vacation.  Immediately the teen son was able to keep his regular hair style when changing into martial arts clothing, but the father's hair still continued to change to the long hair.  When the father gained another level in the martial arts skill, his hair style finally stayed the same as the style I've selected and locked for all his other outfits.  When the teen son gained another level of martial arts skill and changed into a new coloured outfit, he randomly acquired glasses that he wears for martial arts even though he didn't have any accessories selected with any of his other outfits 

I have no mods or cc in my game aside from the Sims 3 Store items that I purchased or were given to me as gifts.  I am fully patched and the latest patch 1.8/2.3 has fixed a few of the bugs I was having in my game, but I am still finding bugs that either were not fixed by the latest patch or are apparently new bugs that came with the latest patch.  These problems are experienced with my Legacy family that I was playing for many months before World Adventures was released.

- I recently had the age reset to the first day of the young adult life stage when I directed my sim to change her appearance with the dresser; the sim had recently moved to a new house and was on the last day of her YA stage when I got her to change appearance (the extra information may or may not have anything to do with the re-appearance of this bug that was supposed to be fixed by 1.8/2.3 but I thought I would provide as much information that could be relevant)
- when I change a sim's hair style and make sure the lock icon is closed (to apply the hair style to all outfits) the selected hair does not apply to the martial arts clothing.  This is happening to me with a base game style that is supposed to be available for all outfits, and I wonder if this bug could be connected to having certain hair styles from the sims 3 store installed in my game.  (Hair styles I'm questioning are the "All Banged Up" for males and princess tiara for females--these styles are only available selections for everyday outfits in my game.  Does anyone know if store content has been updated/is compatible with World Adventures?  Uninstalling these styles has not fixed the problem, at any rate.)
- charisma skill stats (specifically funny jokes told) reverts to zero when any of my sims transition from one location to another
- value of cut gems and smelted metals held in the inventory always revert to their uncut/unsmelted values when the sim transitions from one location to another
- family tree data lost or corrupted and family tree information becoming inaccessible for some sims in the active family (this bug first appeared after travelling of course, and after reloading and getting my sims home safely, this bug eventually appeared after nearly a sim week of playing the family in Sunset Valley and not travelling at all.  It was caused by travel, I'm sure, but this bug's appearance was very delayed the second time.)
- the textures of my sims' trash compactor got messed up after a failed repair job set it on fire.  I clicked on the appliance and selected the "replace" option.  The trash compactor looks normal, but when I attempt to recolour it with CASt, it shows the basic metal as being a wood texture instead, and any attempt to change the pattern or colour of the appliance results in a totally messed up, difficult to describe mess.  It is the only messed up item on my lot, but deleting it and buying a new one doesn't fix it