WHY ALL THIS CONFUSING ACTIVITY BY THE FBI?
Since Obama also communicated on Hillary's unsecured email server, both President Obama AND HRC would be subject to prosecution for violation of national security issues if the FBI were to bring a charge at this time. Since Obama is NOT connected to the Clinton Foundation, nor to the pay-for-play scandal, Obama will not be prosecuted for those crimes. However, both Mr & Mrs Clinton may be prosecuted for the pay-for-play scandal, without involving the current sitting president.
Thus, the FBI appears to have made a strategic decision to place the national security issue (email scandal) on hold for now, and focus attention on the Clintons' pay-for-play violations.