js-marker-clusterer | marker clustering library for the Google Maps JavaScript | Web Services library

I've put together a map with clusters. The idea was that cluster's color should depend on the color of markers inside: if there is a red marker, cluster is red; no red, but there is a yellow marker, cluster is yellow; no red and yellow markers, cluster is blue.

This only works as expected at specific zoom levels. Fully zoomed out it shows blue cluster, however there are red markers in there, so I expect a red cluster. When I start to zoom in and the map shows multiple clusters, most look right, but in some instances this offending behavior repeats, it will group red/yellow/blue markers into blue cluster, I expect red. Same with Yellow + Blue markers should form a yellow cluster, not blue.

According to this setCalculator function runs for each cluster individually, therefore I was expecting consistent behavior, but instead we have mixed results.