Microsoft on Tuesday revealed that a Yahoo! email inefficiency was the culprit of a phantom data bug affecting Windows Phone 7 users. Yahoo! apologized for the bug initially, but later issued a second statement claiming Microsoft’s IMAP implementation was unique on Windows Phone 7 devices, and this was the root cause of the problem. Programmer Rafael Rivera decided to launch an independent investigation into the matter, however, and he posted his findings to his Within Windows blog on Wednesday. In short, Rivera contests that Yahoo!’s IMAP email issues are not confined to Windows Phone 7 devices. He goes on to demonstrate that standard IMAP requests sent to Yahoo! email servers return excess data that falls outside IMAP protocol. Yahoo! has not confirmed or denied these findings.