Given that it has the volume cover and contents page and says “volume raw” in the note at the back, it’s based on the volume release. As the chapter title is placed differently to the earlier release and that came out before the first tankoubon was even was released, it can’t also be from the tankoubon. The image quality in the magazine is pretty much identical however so perhaps it was ripped from ComicWalker?The art is different (as in better). Was this translated from a different release?