d4rkm4tter: The difference in rating makes total sense, as in the problem with higher rating, the first line hane is not accepted as correct. But I can't find a reason why the first line hane shouldn't work in this and 459. Sure, the outside is a bit weaker in 459, but I think it should work in both problems. So I added it as correct solution in 459.
posetcay: Opponent's shape is very weak, so there are multiple moves that kill including T3.
TwT: #Boss-to-decide
Duplicates in same collection.
(a) it is for educational reasons as learning objective assessment
(b) to alter one slightly
I prefer (a). And simply overwrite one with the better review-tree?
d4rkm4tter: Duplicates in the same collection should not happen. This and 459 are not the same. The Cho Chikun collections have sometimes oddly similar problems, but they are still different. In other collections I would say replace it with another problem, but here it is the textbook content.
Lucas Groenendaal: This problem is a duplicate of problem 459 from this collection (https://tsumego-hero.com/tsumegos/play/3427) but that problem is marked as 3D difficulty while this is 2k.
Opponent's shape is very weak, so there are multiple moves that kill including T3.