Some of those that received their iPhone 4 before today’s official launch have complained about screen discoloration. Specifically, a yellow blotch on the bottom of the screen is showing up on some phones. However, the discoloration may not be permanent or a defect with the phone. In fact, it could be a problem resulting from how quick Apple is manufacturing and shipping the phones.

Apple is using a bonding agent called Organofunctional Silane Z-6011 to bond the layers of glass. Apparently, Apple (or more likely Foxconn) is shipping these products so quickly that the evaporation process is not complete. However, after one or two days of use, especially with the screen on, will complete the evaporation process and the yellow “blotches” will disappear.How do I know? I was involved in pitching Z-6011 to Apple.

Some early iPhone 4 shipments have defective screens, missing bars [AppleInsider]