Rusted Stucco weep screed

What would cause exterior stucco weep screed to rust after 12 months? No contact with earth or water (like sprinklers). Home is new and builder is telling homeowner that this is common. Is there a chance that stucco mix could caused reaction? Home is in Arizona (dry climate).

Possibly fertilizer? Got any pictures?

Mary Ann, I’ve never seen that here in South Texas. That galvanized material shouldn’t rust.

Maybe its not galvinized. Cheap material from south of the border.