I cannot control temperature in Smarttings (DHW / SAMSUNG air to water pump) Zone control is fine

Hi, this one is mystery to me. I am using Smartthings app to control my SAMSUNG Air to Water pump. Since few days ago, I am unable to control temperatore for DHW in the app. I can control it on the device itself only. However in app I can turn heating of the water on/off or can even select mode economic/standard/force. But temperature is always displayed as 24 degrees. If I move slider, it will shows waiting icon for a few seconds and then return back to 24 degrees.
Had a SAMSUNG technician here for check, but he claims he changed nothing on teh device to affect the setting with the app.
I have same second device connected in the app, this is based in my mothers house, and for the second device I can control temperature and all other basic functions properly. So, I know this must be somehow set on the device despite claims from technician.
Any thoughts what setting has changed and where I can reconfigure?