Thanks Jeff. I agree that someone in the stucco industry needs to take a look at it. The builder is telling the owner that this is normal and they just need to do maintenance on screed. Wow. What is kind of unusual is the areas where the weep screed is about 1/8" of an inch away from stemwall, there is no rust. Just where it is flush against concrete stemwall. Could it be possible that there something in the concrete mix that could be causing this reaction? I’m stumped. I know what to call it out as, but I guess just for my own knowledge I would like to know the cause.