According to Bloomberg, one of Apple's senior engineers raised concerns a year ago over the potential for the iPhone 4's design to cause dropped calls.
Ruben Caballero, an antenna expert at Apple who worked on the device, spoke with management last year about his belief that the iPhone 4's design could cause reception troubles, according to Bloomberg sources. A "carrier partner" also expressed worries over potential antenna issues. All of which backs up what qualified third parties have said since the iPhone 4 "death grip" was first discovered. Apple has declined to comment, but will hold an iPhone 4-related press conference tomorrow.