I encountered a problem with the viewer on safari browser on Mac OS . When the model is loaded in the viewer with the correct textures in the next moment the texture changes by itself and after that the viewer crashes and loads the model again and the same thing happens all over again.
With chrome and firefox it opens with compatibility isues and allowes 360 rotation only in horizontal plane. (Only on MAC on windows is OK).
Here you have a link of one of the models .
On iphone it looks great but the problem happens only on MAC.