Bug in code not being able to set an IO before and after the sleep command? Wouldn't this would be an impossibly difficult bug to create?
As for minimal advance powering up signal for external hardware, why not put the MCU into sleep in 32KHz ultra low power mode, then when waking up, in 32KHz, set the IO on and wait that infinitesimal small delay before changing the MCU clock back to full speed as a means of minimizing power consumption?