I had both problems. In Hungary in some repair shops they change the lights with bugs in warranty, in mine they cleaned it...twice. As they came back 1 day later. I guess they just blowed it with compressed air. Theres a hole on it for condensation water to escape. Sadly Skoda missed to put a wire or sponge or something to the hole. Bugs can enter there.
For the errors. They've replaced my battery too and many others also. The error is gone, but I'm sure thats not how the car should notify my that the battery is in bad condition. It must be fixed with software update some time later. Even if the voltage is low, it could enable the systems a few sec later and tell me to replace the battery soon. Since that i dont have problemy (so far) but I didnt have heavy snowing here sadly.