I don’t usually cheat skills, but sometimes the mischief skill gets obnoxious and I either lower it or get rid of it entirely (though it does always come back eventually), so I have no idea when this problem started for me. It’s been a while since I tried to lower a sim's skill. Anyway, I’m on PS5, have just about all the packs except the last three or so expansions and only the kits we got for free. As others have experienced, I can raise skills, but they will not lower. And since they won’t lower, I also can’t set them to zero to get rid of them. I can raise them just fine. As soon as I hit enter, I get the notifications that the skill is going up. It’s really frustrating lowering them hasn’t been working. Just wanted to add my voice to the chorus.
