This link says very explicitly that it did show people were discouraged from working, making the experiment obviously a failure.

> Among all the people, only two key groups were found to be discouraged from working by the Mincome project – new mothers and teenaged boys, who, instead of entering the workforce at an early age, decided to study until grade 12, increasing the proportion of students who graduate high school.

Maybe I'm misunderstanding you, but neither of those outcomes sound like failures? They sound like a net positive for society. New mothers get to spend more time with their children, which has a ton of societal benefits, and teenaged boys decided to study more, and become more educated, something that also helps society out a lot. I admittedly didn't read the entire link yet, but both of those sound to me like a positive outcome of UBI, or at least neutral.