It is impossible to control for all variables, all of the time. Dronelink acknowledges that the real-world is hard to predict, and that pausing missions should be a rule, not an exception.
Missions can be paused manually, by tapping the pause button, or automatically, as a result of various factors including signal loss, low battery, RTH activation, etc. Paused missions are displayed at the top of the list in the native app as In Progress.
In Progress missions can be resumed by tapping Load Mission and then by tapping the Play button in the flight dashboard. The Dronelink flight controller will access the last known state of the drone, gimbal(s), and camera(s) and use this information to restore each sub-system to the exact state that it was in when the mission was paused. If the drone was in motion when paused, the flight controller will resume the mission from a slightly offset position to allow the drone to ramp up to the proper velocity by the time it reaches the pause location.
There is no limit to the number of times a mission can be paused, and there are no restrictions on resuming a mission with a different device, drone, or even user profile. Resuming missions across users does require a team account, however, as the users must be members of the same team.
In Progress missions can also be aborted by tapping ... > Abort. Once a mission is aborted it cannot be resumed.