There's likely some confusion because Rindou drew some art for this one hentai.org/s/6c0796343d/1783300-214 Example on pixiv: https://www.pixiv.net/en/artworks/15519577 And it's assumed, though I don't know if it was ever conclusively proven, that the art of her in "[Yuukyuu Shinden] Critical Bad End" was drawn by them as well. Gelbooru peeps are certainly convinced of this: https://gelbooru.com/index.php?page=post&s=list&tags=tsukikage_kuon+rindou_%28radical_dream%29
That said,some of the pics of her, particularly the bonus, MIGHT be VERY old Rindou art. The first variants of Sayaka and Sakuya that many Rindou fans know and love popped up around 10 years ago, but Rindou's been drawing for notably longer than that, and those who remember stuff like "Ryoujoku no Rensa" will likely remember that once upon a time, their style was quite different from what we've gotten used too these days.
That said, while it's possible that Rindou contributed to this... it doesn't seem very likely. I could be wrong though.
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