It's not fog, but humidity, I guess.
I've had this problem with both shoes of the pair shown in the picture. Sent them back and bought a new pair, same problem again.
Is it something I should worry about? Anyone know what this is?
When I noticed this I sent them back and bought another pair of air max 90's. I came home from a walk and noticed the same bubble problem on the new pair.
Is anyone familiar with this? Is it something to worry about?