Hi, welcome to the monastery.

Your code didn't specify any position for labels. If you want them on top of the graph, use graph coordinates with 0,0 being lower left and 1,1 being upper right. So change your code:

$chart->label(
    text      => "Labeled at (-2, 0.5)",
    fontcolor => 'blue',
);
[download]

$chart->label(
    text      => "Labeled at 20% from left, 25% from top",
    fontcolor => 'blue',
    position  => 'graph 0.2, graph 0.75'
);
[download]

You'll also want to close that bug report :o)