Bear with me as I try to explain this issue, I havent seen any other posts regarding this.
During the course of 2 missions I have experienced this bug.
On one mission me and 2 other players are staying grouped together working on a quest line, near the end of the quest one of us died resulting in the respawning character re-spawning on the other side of the map, because they were not able to rejoin the group the mission failed and we all had to disband and go our seperate ways to work the quest alone.
The player that died spawned way on the other side of the map, more than 350km away from the other players.
Had exactly the same problem last night on a mission called something like Point Counterpoint. After we had done the away team instance and a couple of us were destroyed immediately. We respawned 400km away and when we tried to get back to the fight we hit an invisible wall.
Two of us did try going back to Sector Space but when we re-entered the area we were back at the start of the mission, the others still couldn't get back to the klingons to continue the mission.
Though it is a bug, there is a workaround for in Point Counterpoint - if you have died, exit to sector space, then click the "conitnue" button in the bottom right of the UI - best if all team members do this together, cuz you re-enter right on top of the enmies