Advanced Poll: circle diagram problem

I discovered that when an item has not much votes, the color of that item in the circle diagram (grahic template: results) is always the color of the first item.
If there are more of those items, than that's for every item the color of the first item, no mater if it's 5th, 9th or whatever the place of those items might be.
There is a critical treshold between totall votes and the votes which gives an incorrect display, but I don't know which treshold it is.
For instance: with a totall of 170 votes, 4 votes is incorrect displayed, 5 votes is okay.
With 138 votes, 2 votes is incorrect, 3 is okay.
With 1041 votes, 22 votes is incorrect, 32 is okay.

Known problem?
With a solution?