Short description of error
even the exporter is set to 100% opacity the uv lines are semitransparent
Exact steps for others to reproduce the error
please check the image, the problem here is that wihtout a 100% consistent opacity is difficult to isolate the uv islands in photoshop or other softwares.
overlapping more times the same uvs to get rid the semitransparent areas gives error on the edges due to the antialiasing.