So, I ordered a graphite backlit GBA SP off Amazon and it arrived today. It's in rather great condition, except for one thing I've noticed... the A, B, Start, Select, and Light buttons all feel "stuck" the first time I use the system for a play session. That is, I have to push on them a bit hard before they seem to "snap" and go down. After doing this once or twice per button, it works fine. However, after not pressing a button for an extended amount of time, it happens again. Any idea what's up? I don't have this problem with my pearl backlit SP, and comparing the buttons on the two, they both look the same except for the color, so I don't think that the ones on this system are 3rd party replacements or anything. Any idea what I can do to fix this, hopefully without having to crack open the system?