Whenever our battery runs to zero, or if we have a reset due to voltage droop, the unit will not auto-connect and the user is forced to "forget" the device in iOS bluetooth settings and then re-pair with it.
The device is running SDK6.1 SD7.1. It's a nRF51822.
Perhaps this is because the pair-bond keys are lost during reset? Can the necessary information be stored in non-volatile memory?