The current full control API does not require robots to wait at waypoints until designated time before proceeding with the rest of the path request. The robot is free to navigate through the entire path request.
Robots are allowed to skip ahead when path requests come in. In the scenario where the robot is already navigation through A->B->C, and is between A and B, a new path request A->B->C->D comes in, the robot is allowed to continue to B->C->D, instead of doubling back to A first.
Mentioned in https://github.com/osrf/fleet_adapter_mir/pull/14#discussion_r963280256
To summarize again,