In a memo shared with Apple Stores and Apple Authorized Service Providers this week, and later obtained by MacRumors , Apple provided technicians with guidance on how to diagnose and address the iPhone Duo’s inner display cracking issue. If a customer reports the issue, Apple advised technicians to inspect the iPhone Duo and repair or replace it in accordance with their standard procedures. While the instructions themselves are straightforward, the fact that Apple issued an internal memo suggests the issue is widespread enough to warrant official guidance. Apple’s memo said the issue affects a small number of iPhone Duo units, which is consistent with what it said in a public statement on Monday. "We are aware of an issue impacting the inner display on a small number of iPhone Duo units," said Apple, in a statement shared with MacRumors . If users experience issues with their iPhone Duo display, they should contact AppleCare for a replacement." You can get support on Apple’s website or by calling 1-800-APL-CARE in the U. S. and Canada…