It sounds like you're saying their total after-tax income would decrease if they worked more hours? I'm not sure how, because that's definitely not how income tax works (Italian or otherwise).
Somewhat similarly, in the USA there is a "welfare trap"[2] where earning more income would reduce other benefits (eg housing, food) enough to result in an effective >100% tax on income.
[1] https://publicnewstime.com/travel/explained-the-pros-and-con...