That isn’t behavior that occurred in the pilot problems they talk about it.
It will take 15 or 20 years before any UBI could be considered permanent enough for a majority of people to change their work habits.
Not to mention that most people enjoy working as it gives them a sense of purpose.
I do believe that people would still work though. Personally I would like to do a useful job with real benefit to society, but the low pay makes it not feasible. I would still want to work part time at least instead of not at all.
Barring AGI and a swarm of drones/nanobots, you still need people to work. Money is just a unit of exchange. If everyone on earth has a billion dollars, but nobody wants to work, nobody is going to be driving around in lambos.
Utopia or dystopia? Probably both, unevenly distributed