Spilled water on mouse, now it shows battery level even when it's off

As the title suggests, I spilled a little bit of water on my Logitech G900 mouse, and it works 100% fine, except that it's showing battery level even when I turn it off. It's only supposed to show that when it's plugged in to a charger. I know it's weird, I have never heard or found anything like that. I don't have a dissasembly kit at home, but if this suggests that there's a bigger hardware problem, I can get one and take it apart. Should I do so?

Question by G900MouseOwner on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.