Cannot stop T58 Red LED Flashing

[ENFORCER]

Hi,
I have 16 x T58's deployed in a home.
We have been trying to stop the red status light from flashing, aside from inbound calls.
However, after a period of time, all the handsets will start to flash red slowly.
I have removed any missed calls indicators from the PBX (Vodia)
It seems to be with the T58 handsets. All are on FW 58.85.0.5

I have the following in the cfg:
phone_setting.common_power_led_enable = 0
phone_setting.talk_and_dial_power_led_enable = 0
phone_setting.mail_power_led_flash_enable = 0
phone_setting.ring_power_led_flash_enable = 1
phone_setting.mute_power_led_flash_enable= 0
phone_setting.hold_and_held_power_led_flash_enable = 0
phone_setting.missed_call_power_led_flash.enable = 0

Is there any way to see what is causing this red light ?
Help

Thanks