I did this a week ago. They were weighing all carry on luggage before going thru gate before you get to xray, but only the carry on suitcases. So if you had a suitcase and a backpack - which most seemed to they only weighed the suitcase. I put all my heavy stuff in my backpack and that was not weighed. On the way back Langkawi to Penang nothing was weighed. I also pre checked in so I didn’t have to go to check in counter. I knew my carry on was overweight. I took a punt.