I recently finished a simple model and was practicing adding different materials. I have done this before and never ran into this problem. I created a material (bottle) and applied to the cylindrical shape. I then tried to create and apply the steel.001 texture to the face that is highlighted in the first image. I also applied this on several adjacent faces to better show the effect happening. I additionally tested applying the steel.001 green material to the long face to the right of the highlighted face.
I'm getting a strange result where the material is either overlapping onto other faces or not taking up the full face, which is something I haven't seen before. I'm not sure whether this is a glitch in my program, messed up setting, or a mistake I made, but I've opened and closed the program several times and gotten the same result.