Pie chart with negative numbers (strange cut off)

I am doing pie charts of several disk metrics and came across this (at least to me) strange behavior:
first pie chart:
query any kind of field.
second pie chart:
query the same field multiplying it by -1
Select bytes or kbytes for both metrics (not necessary to reproduce)
The values on the pie chart are not only different in sign. All the negative values are cut off (or maybe rounded) at their highest unit. E.g. - 2.3 KB become - 2 KB, - 4.38 M become - 4 M
It would be cool if the behavior of the panel for positive and negative numbers was the same, or am I doing something wrong?

may be you want to post or create an issue at for the developers to look at

Please check/post in this repo regarding pie chart panel