Ray notification LED not working when screen is off

After updating to ICS 4.0.4 green notification LED stopped working when screen is off. It does not work for SMS, email (I use K9 Mail), missed calls. However if screen is still on WHILE receiving new email or message the notification LED works as intended.

Anyone been able to fix this problem? It loses it's purpose if it only works when I look at the screen (screen is on). I know of a Light Flow app, but I would like a way to make it work like it should first (without third party apps).

http://talk.sonymobile.com/message/204221#204221