I wonder what that implies. The people who bookmark it without liking it want to see where it goes but didn't "like" the chapter that much? Or do they just not push the like button ever?
Look on the bright side. It can be something like this -
'Oh, this looks interesting! But I don't have time to read it, so I will throw it into my favourites and will return to read it later - one day, when I have time... I am sure I will read it!~'