Hi Ivo, I couldn't believe my eyes when I purchased the one that looks like mine today. I was showing it to a friend whilst having coffee at a bistro. The colour changed purple whilst in natural light, as can be seen by these pictures attached. I did question the owner and she assures me that these are genuine Murano brandy Glasses, made in italy and that she frequently purchases Murano glass on her visits. I only can take her word. I've also included a picture of the label to assist you. I've read some of the past threads on this site and currently not come across this type of label that maybe misconstrued as being what it shouldn't be. Therefore if you have any evidence to substantiate your reasons, which I'm sure are genuine, it would be interesting to know. I don't really know a lot about brandy glasses and hope I have made that very clear, so will solely base your experience and knowledge as a step forward in finding out who actually made these. I very much appreciate your concerns.
Oh! I must also tell you, that when I arrived home I decided to carry out the UV test. The concentrated areas were the colour is more visible, that is around the lower base area of the bowl and neck. The colour changed to blood red. This does not mean anything to me, but maybe of some help to you.