Unfortunately this assert does not seem to work as expected and causes errors (in dev mode)

Code:
public class BarSeries<M> extends MultipleColorSeries<M> {

  private void calculatePaths() {
    ...
    double value = yFields.get(j).getValue(store.get(i)).doubleValue();
    assert value * minY >= 0 : "Cannot mix positive and negative values in BarSeries.";
    ...
  }

}
In my chart I have fairly large (Long) values, this conversion to a double and then multiplication seems to result in this assertion error even when there are no negative values in the data.

In my data I see values ranging between 0 and 5587930998, could it also be because I sometimes have a chart full of 0's ?