[Karthika KK]

After WP 8.1 I found this weird issue going with my mobile. In my L520, whenever I switch on my ringer it doesn't work until I increase my volume. If I don't then the phone remains on silent.
Another thing I noticed today is yesterday night I kept my mobile on both vibration and ringer off so that I don't wake up from notifications. Morning I woke up to found out my ringer is on, and im getting notifications noises.
Please solve.

[Muessig]

Honestly it does sound like a bug. Try doing a soft reset - press the power button and the volume down button at the same time for 10-15 seconds or until you feel a vibration and this will perform a 'factory reset' on your device but still keep all your personal data.