The Y output in Random Sampler aka Marbles seems to always work based on the Steps control.
In the Marbles hardware, by default, Y is smooth / slewed even if the Steps control is set to a steppy setting for a quantized scale. By default, Steps controls only the X outputs.
From the official Marbles manual:

The smooth Y output is extremely useful in patches, e.g. as a sort of smooth random LFO.