1. The first floor's supposed to be rent free, it's not
2. Training stamina drain can be a bit odd, because it looks like it's deducted by day spent training and each training request, rather than by time spent training. So, if you start two idols training at the beginning of the day, but one takes the entire day to train a point, but one only takes half a day, they both lose 7 points of stamina. This can have some strange effects, like the fast training trait being far less useful than you'd imagine, because stamina is a bigger constraint on idol activity than time, and training low stats effectively using a lot more stamina than training high stats over time (eg. if you take 5 days to train 8 points in a low stat you'll lose 56 stamina, compared to 35 stamina if you take 5 days to train 5 points in a higher stat). I'm not sure if this is intentional or not, though. (Sorry if this is hard to understand, I explained it as clearly as I could)
3. I got one incident of a text bug where I asked idol A about gossip and she said that idol B was dating idol B
4. Sometimes blaming a staffer for a scandal removes the scandal points, but doesn't fire the staffer. I think this might happen if you take this action while the game is paused.
5. I got one incident where a concert didn't start production when I put it in the producer's room (time was definitely running)
6. It seems like if you hit 100% opinion with a demographic, the opinion will reset to 50% when you release a single, or load that save
7. Sometimes idols being styled will be counted as idle, so you can assign them to two rooms simultaneously
8. The stamina drain for going to France in the World Tour is only 10%, compared to 20% for every other country (again possibly, but not probably, intentional)
9. Scandal points at the bottom of the screen sometimes display incorrectly, for example I once got 4 points, but two idols graduated and this dropped to 1, but it still said 4 (the tooltip when I moused over said 1 though, and it correctly displayed 1 when I reloaded the game)
10. Theatre shows don't seem to use stamina, given how much money it makes I'm sure this can't be intentional
11. There doesn't seem to be any age logic for scandals involving adults and idols under 18* (this could happen in real life, but at least give an extra option for the player to call the police)
12. When you combine a 2-shot (-75%) with the stamina drain for all single releases (-30%), it's basically impossible to do one without a severe risk of injury, which seems very over the top even if it's intentional
13. If your floor rent multiplier is high enough, additional cafes (or even the first one) can cost more in rent than they make (this applies to theatres too, but they potentially make for more money so it's much less likely to happen). Not sure how this could be dealt with, maybe make assigned idols increase income directly instead of sales? Again, could be intentional but doesn't seem logical
14. When you improve the lyrical/dance/music styles some of the ones that have negative modifiers improve and some get worse (so some with a -10% modifier will be -8% at level 2 and some will be -12%). I'm sorry, I made a note of some of the styles this happened with, but I deleted it by mistake.
15. Lastly, this is something I'm not sure about, but I'm worried that the sales bonuses for having a handshake event for singles don't work. In games where I have enough of a money cushion to start producing physical CDs with handshake tickets I look at the units sold per fan and expect to see a noticeable rise (with a fanbase at around 65% hardcore), but I never do. It's hard to test this with any accuracy because there are lots of variables, but I'm not sure it's working properly.