When you check the reflective items carefully, you will find there is a line on the surface of these slapwrap or badge etc. sometimes it is a very thick one and sometimes it is a very thin line, as seen on the images to the right. The top image is a 3M one (notice the small triangular logos on the surface) and the bottom images are standard materials such as reflexite.
Reflective vinyl raw material come in different size, USA material comes in a roll (for example, 3M material is in size of (45.7cmX100meter) while China made material comes in a sheet (45X45cm). Every 22.5cm on the surface for the raw material, there will be a line. This is not a quality problem. Because the size of the moulding which produce the reflective vinyl is about 22.5X22.5cm. So it will not be possible to avoid the line.