It was. They just never uploaded the last season here.
You might ever heard back then that few of korean webtoon artist want to charge the illegal uploader or even sue some illegal website (i believe including mangago) for uploading their webtoon without their consent and share it for free (which mean they didn't get the money for their hard work). That's why the safe way not to anger them anymore (at least in this website) is not to upload the remaining chapter or even delete all the chapters... of course there is other website that stubbornly still upload the webtoon, haha
Some were actually sued! Not sure if by this artist, but I read there were a bunch of manhwa/manga websites that were under a lawsuit because of illegally publishing the stories!
Regardless, you can still find the rest of “Painter of the Night” on Manga Forest!
was this not? i never ended up finishing it but istg i eventually got the ending spoiled-… was it never uploaded here?