Well, the colour on my claret pair is not as uniform as it first was - I usually use Kiwi Cordovan. Not glamorous, I know, but it works. I have not experienced the pink spot issue.
OK, well it must be me then. It happens pretty fast. Even droplets of water from washing my hands will do the same. Walking under an umbrella in very light drizzle will also cause the same very noticeable spots; where the wind blows the spray onto your feet... it's a water contact thing. The micro droplets of spay from a damp pavement will also cause spotting on the sides. I must remember, there are more important things in life to consider