A brewing stand with a full set of bottles and an ingredient produces no stronger a signal than a full set of bottles on it's own.

Though this is not technically a bug it is still an issue as it renders automatic brewing stands (which were functional in some 1.5 snapshots) impossible to do without using a clock (which can cause server lag if not done properly, as well as being more resouce intensive).

The simplest solution I can see from my understanding of the system is to reduce the maxiumum stack size of the ingredient slot of the brewing stand, this will mean the effect of a single ingredient on the signal would be measureable while not requiring any comparator logic differences to be hard-coded, plus, why would you ever have a large stack of ingredients in a brewing stand anyway?