Are you, by chance, running any app killer program? If so, you need to raise the "security" level high enough to prevent the app from killing system level programs. When that system level program starts back up it will default the phone back to factory settings. I discovered this when running Advanced App Killer set to the "LOW" security setting. I would set a live wallpaper then after I'm done with the phone, I would put it on standby by quick press of the power button. The App Killer was set to shut down most background running program on "screen blank" mode and it was shutting off the system program that controlled the live wallpaper. When I pressed the power button to wake the phone back up, the live wallpaper was gone and replaced with the static plain wallpaper from before. When I raised the Advanced App Killer security level to "MEDIUM" and made sure it wasn't killing system files, then the live wallpaper worked correctly without resetting every time I would put the phone to sleep. Also, any app you have that relies or controls the NOTIFICATION sound, check it's OPTIONS setting to make sure that it's not the app that's lowering the volume after using that app.