Investigating Flares seems to be particularly buggy at the moment. The requirement is 2 ILBs, but I had to dispatch a third to handle the third patient on this mission, despite all 3 being "in" one ILB, and now i've had to dispatch a coastguard heli towards to provide Crit Care despite all 3 of these ILBs having Crit Care Crew.
Update: Actually need to cancel and re-dispatch the ILBs to get the mission to update so I could send them to a station for hand-off
If you leave the mission to clear before transporting then it works fine. I believe this has been flagged up along with the possibility of having a ALB count as a ILB.