Thats not the art it's just the quality of the panel. Its like being on yt and having a video go from 1080p60 to 480p. Not intentional but for some reason it happens
I don't think you got what I mean. What I mean is they usually blur the line art a bit to indicate that the characters are moving (usually fast movement like punching or kicking). for example in this chapter they blur jinwoo feet and hand in one panel to indicate that he is jumping and swinging(?) his hand but the rest of the line art is sharp.
Its not exatly bad, but blurring the line art so much in a fight is usually only used in epic fight to differ them from usual fight.
Its just my opinion that they blurred it so much that it take away my enjoyment in reading it. Maybe I just really like clear lineart
Lately I don't like the art for SL, too many fuzzy line art to indicate movement. Almost all the panel for fighting the lineart is fuzzy, its okay if it was used once in a while but if they use it for every fighting scene it will be overdone. I just like a more sharp and clear lineart I guess