So I encounter some wierdness for models having the same UV-coordinates, but imported with different materials from 3Ds Max.
Tried to describe what actually happens as briefly as possible below:
(https://i.ibb.co/PYHvyvd/img3.jpg) (https://ibb.co/FWTL1LF)
(https://i.ibb.co/t2YDjQt/img1.jpg)
(https://i.ibb.co/8Dj3c5G/img2.jpg)
Bottom line: Even though the boxes hold the same UV coordinates. Only the object
which holds a bitmap as texture during import will have working UV coordinates?