I would like to know too.
I thought it was completed too. I had it in my "already read" list for a while but kept getting notifs so I went to check and on-going. Personally didn't even like the webtoon that much so I just went ┑(￣Д ￣)┍ not gonna bother reading it. To me it's completed lmao.
I have heard (from others on this site) that Lehzin treats some artists poorly and has discontinued a few series - not sure if this is true as I have no first hand knowledge ... but might help ╮(￣▽￣)╭
As far as I know, the author left it open because, in the future, they might get more ideas for the story (as it has happened before, since originally they planned only a few extra chapters after the main couple). Maybe that's it (also, tbh the last couple did feel pretty unfinished to me so there's that too).
One of my favorite manhwas "If You Hate Me So Much" is marked hiatus on lezhin. I thought it was completed. Can anyone explain?