Line block - line thickness

I'm currently redesigning my front page and I'm using several horizontal lines as dividers (line block). I basically just kept duplicating the first line and then moving it to a new place. 

And now I see that some of the lines are thicker - as though bold - than others! There seems to be nothing I can do to change this. They're all in the same section, all look exactly the same when I click, drag, or look at their editing options. It's not a biggie but it bothers me because it makes no sense! 

The page in question is here: https://www.wildspiritscoaching.com 

Any ideas?

@SibylleLeon They all look the same on my end. Can you share a screenshot of what you're seeing?

Looks good to me as well.