I can confirm that I had this problem too, twice. That's why I posted elsewhere a question about the precise conditions in which we may expect ice on the wings. It appears that it can occur with temperatures >0° C, with a dew point closed to the these ones. And it that case, sometimes, ice is not depicted.
Just one example : on a flight online on IVAO, actually, I had ice on the wings and ask the ATC guy to stop taxiing for de-icing. He confirmed that there was no reason to de-ice according to the weather conditions of the day. The hour of the flight was at the end of the day, not in the morning.
Just for information. By the way, I like this plane very, very, very, much...