I think I found it.
Falkland Systems Ship Services.
I was going through the Creations first, one by one. When I disabled Falkland and loaded my game. I was able to enter the second area of Heimdall Station. I proceeded in for a few moments, then saved and exited the game. Relaunched and loaded the save - it came up without an issue, and I was able to complete the mission.
I guess now we just need to see if disabling that mod works for anybody else who had this happen and has it in their mod list.
Hope this helps!