Yes of course, your know if one people always wear eyeglasses for several years, the eyeglasses frame will give some weight to his face and the bridge of nose. Thus the shape of nose and face will have some change from the original one. Moreover, the myopia glasses itself has some function to enlarge the appearance of the eyes as well as the face. You are get use to the former appearance of your friends, when he change the eyeglasses into the contacts, the weight of glasses are lower, and the appearance enlarge function is disappeared. His original familiar appearance then changed to a new one, so you find it is strange, that is normal and you will adapt to the new face of your friends quickly!
I have the same feeling with you when I see one of my friends doesn't wear her glasses as she usually does. But I think that feeling will disappear when we get use to it.
I'm not sure whether your friend's eyes get out of the original shape or not, if so, it's really strange. For those whose eyes are really changed through the years of wearing glasses, they'd better not take off their glasses.
Generally speaking, everything will be what you think. You think your friends weird without glasses just because you have been used to the appearance when they wear glasses. Actually, wearing glasses for long time will affect the shape of your eyes, especially the muscle between your nose and eyes. That is to say, if someone has been wearing glasses for long years, and when he put off the glasses, you will find the eyes have been sunk. Besides, you will find there are two marks between nose and eyes. On the contrast, if you have been wear glasses for short time, the shape of your eyes will not be effected and then you put off glasses, it will be just a little strange for a short time, say one hour, later you will know there is no difference between with glasses and without glasses. I just told you my personal feeling. Thanks.
From personal experience, i would say yes, People always look weird or different when they change something about their appearance, because we are accustomed to seeing them that way. It's just like when you get your hair cut or get braces on/off... after awhile they look normal again.