0 means disabled, thus equal to unlimited number - infinity... Any value larger than 0 activates max sample intensity parameter .... so value of 1 will introduce extreme clamping, value of 10 will clamp samples normally, and values above 10 will further reduce sample clamping up to the point where value get's so high results will be similar to max sample intensity being disabled (set to 0)
So yes, this is a feature...