Agree we may be making too much of the handbag conundrum but it's interesting. It's also unusual for L&P to forget, or over-ride such details. L&P is usually immaculate in that resect, and almost certainly goes over the finer details painstakingly before each update release.
Study the above image of Sophia locking her classroom door (classroom 11). The classroom key is relatively small and separate from car/house keys so could easily slip it into her jacket pocket, also without it spoiling the line of the garment. Yes, women do think of these things. Also, from a woman's perspective not having her handbag at hand, especially wearing a skirt (no pockets) makes it highly inconvenient in the same way a guy naturally thinks of having his wallet, phone, keys with him all the time. Most guys would never leave these items out of their sight so one has to think like a woman to analyse this.
Now back to the last teaser. She may have simply placed her bag on the floor behind the corner, out of sight of the image presented. This prompts one to think Sophia is witnessing something, or is waiting and wants to remain partially concealed.