Some resin colors react to different chemicals and different temperature and humidity combinations. The most often seen one is where white seems to "rise to the surface" into one of the colors. Sometimes red will discolor and turn slightly orange.

Almost anything is possible because most manufacturers don't subject their balls to every possible combination of chemical available on this earth, that bowlers seem to find.

Usually a good cleaner will remove the imperfection. Sometimes it takes a sanding and re-polishing. Sometimes just use and reabsorbing oil that happens in use will restore it. 9999 times out of 10000, even if the color stays, little or no harm is done to the ball's performance. As for its looks, well that's up to you
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"None are so blind as those who will not see."