Honestly, I've never seen that happen before (which is why I was hoping you could provide some more info to try and replicate it)... I suppose it might be some sort of weird rounding error when dealing with very small numbers?? I know that bar charts go a little wonky with small numbers, (like under 5 - I've seen the incremental values show multiple 1s and 2s...)
If you can replicate the issue, you might also consider contacting Client Care to look at it, as it might be a legitimate bug.
