Custom colors set with pileLabelColor do not "rotate"

[flekschas]

When specifying some custom colors for pileLabelColor likes this:

piling.set('pileLabelColor', ['#ff0000', '#0088ff']);

one would expect that the colors are reused when there are more than 2 categories. (i.e., similar to how the default colors are repetitively used). Unfortunately, this is not the case, no color or black is used for categories > 2.