Those are a sort of smps idd, but are not voltage mode. They are working in sort of current mode, because thats whats relevant for leds. Usually there is a "led driver ic" that does this current mode regulation, and is specifically made for application in led power supplies. Check its datasheet online, and app notes.
So these are supplies for power leds, e.g. probably set to about 50-100mA just to have an idea of the scale. And those leds need to have that much current in them and no more, regardless of anything else. Since they are leds, if current gets more than that, the leds would burn. So thats what it does, it keeps the current to that low level, its job is not to keep the voltage at any level because the voltage is irrelevant.
I would say thats not a failure mode, but probably its actually working as intended.
So these are supplies for power leds, e.g. probably set to about 50-100mA just to have an idea of the scale. And those leds need to have that much current in them and no more, regardless of anything else. Since they are leds, if current gets more than that, the leds would burn. So thats what it does, it keeps the current to that low level, its job is not to keep the voltage at any level because the voltage is irrelevant.
I would say thats not a failure mode, but probably its actually working as intended.