I'll update my thread from months ago as well, but figured it'd be worth mentioning here...
The "re-trigger" function under a given camera's alert properties now allows you to have multiple SIMULTANEOUS triggers, and independent alert execution.
For example, my single front door camera can be triggered by the BI motion detect, or the camera's own internal 'line crossing detection'. The latter is considered a DIO input. In the past, if BI MD was turned on, and someone tripped the MDbefore crossing the line, the active MD recording would preempt the alert for the DIO input.
This meant I had to choose either DIO triggered recordings/alerts, OR BI MD. With this latest fix, BI MD can be in progress (and not send an alert, since alerts are configured to send only with DIO triggers), and if someone crosses the line, the DIO trigger will send an alert.
Thus, all motion is recorded, but only if someone crosses the line will my phone 'ding-dong' push notify. Best of both worlds, with a single camera.