Yes, the line is not selected, but there is still a grey line behind it. Here is a picture with the line selected. Now there are three lines (dashed, grey, and purple)... but it is still only one line. You can see the purple line now, but the grey line is still there below it. Note that the purple selected line is completely on top, but the grey line is only in the gaps.

There is something applied at layer level and it looks like there is a fill.
Can you perhaps hide that stroke panel? And show the complete artwork (not just this small part)?