Strange update behaviour

Hi Gentz, 

  I'm in a dire need of help, because this bug is killing me for weeks now. 

  I got a function, and that function has a simple update query in it: 

UPDATE app_devices SET device_state = p_values[1], device_updateTs = NOW(),
device_changets = CASE WHEN device_state <> p_values[1] THEN NOW() ELSE device_changets END,
device_alertstate = CASE WHEN device_state <> p_values[1] THEN 0 ELSE device_alertstate END
WHERE device_id=dev_id;

 The device_alertstate's default value is 200. update and changets are null by default. 

 And I constantly face a result when the device_state is updated, changets and updatets are populated, but the device_alertstate remains on the default 200. 

  As far as I can tell from the second round and forward it works well. 

  I am simply not able to come up with any reasons for this to happen. 

Thank you very much in advance!

Bests, 

András