i suppose it's possible, although it's nothing i can see or feel. there's are spots up and down the bottom side, random pattern of which the pic is typical. had the board for about a year and a half and it's pretty all i use, it's such a great all around board for this area (SE NC). i'm just wondering how bad it's going to get - may have to go back to see the guy who made it and see what he thinks.
Could it be staining from something you store it on if it was both sides I'd be concerned about seeping. But only on one side could be something as simple as a reaction to what you lean it against. Hope this could help!
Whats the core? eps? inconsistent mixes(highly unlikely in this case), irregular foam formulations, mold,pin sized holes allowing water entry, moisture that was already present in blank(not very likely but possible)alot of possibilities here. The span of time that you stated points in the direction of a water issue. Keep an eye out for the spots getting bigger and possible delamination at worst. Crazy things happen in surfboard building. doesnt mean its not a great board made by a great builder. Im sure if you take it back and let the guy have a look, he will do his best to get you answers and make you happy.
Residual pentane, water or contamination. Pentane is the blowing agent in EPS (expandable polystyrene). It's a little more flamable than lighter fluid. EPS is pre-expanded, aged and then molded with steam and pressure. The process leaves residual pentane and water. My guess is a little water was left in the part (blank) and is now discolored. It could be contamination from the mold, in the EPS raw material or mold release.
Are the dot's pinkish instead of brown? I've seen pink imperfections appear when acetone is used with epoxy, and when spackle is thinned with hard water out of the tap... from minerals in the water... kind of like a rusting effect. That would be my guess, as EPS is usually spackled, then lightly sanded, removing the surface film of spackle, but leaving the little bead divits filled. Just make sure they're not pinholes. Otherwise, it's just cosmetic.
the spots are rust colored - i'll break out a magnifying glass and see if i can spot any imperfections in the affected area (like pinholes). i can live with cosmetic problems, just don't want to see the board rot away from within.