heron: It seems like there are many solution variations which are missing (all still having the same basic ideas). Not sure what the best way to solve that is; maybe the puzzle should end earlier.
caranthir: Most definitely not seki or ko (contrary to what @AtariAnyone said), but it is probably in a wrong collection here (like @AtariAnyone said). If 101weiqi has a seki or a ko solution - well, that website obviously isn't error-free. Probably no website is if it has even somewhat decent amount of problems.
posetcay: This tsumego is way too hard to be in a sdk collection, I suggest that it should be removed from this collection, otherwise people will keep complaining about it.
AtariAnyone : Having this problem in an SDK set is absolute nonsense. Also the solution isn't accurate, it should be a seki or a ko. For those curious it's a 101weiqi 6D problem ?
Ivan Detkov: I disagree with "it should be a seki or a ko". If you disagree with me - prove you are right.
Tarek Barnes:
This tsumego is way too hard to be in a sdk collection, I suggest that it should be removed from this collection, otherwise people will keep complaining about it.