dev_icm trace level not coming back

Hi Friends,

By Default Trace is at level 1 in the system.
We made it trace level 3 and it started to record all the logs.

But when we revert trace to level 1 its not coming back to trace level
1 , still its recording all the traces at level 3.

Only after restart of ICM its coming back to Trace level 1.

can any one tell me the correct reson.