I was playing a Lancer and doing the main story chain having no issues until I hit the quest Dread is in the Air. I had just completed Leia's Legacy. Right after completing Leia's Legacy, the NPC Luquelot in question had no conversation options. I wandered around the area for a while, stood on top of the main story marker according to the map but I could not access the next in line quest. All prereqs had been completed and the necessary level achieved. Vexed, I logged out and logged back in. Now the quest NPC Luquelot had completely disappeared from view and could not be accessed for conversation. I logged out, logged back in and still he was gone, but only for me. During this time I noticed many players going to Luquelot's location whereupon they stood for a few moments and moved on. I had a friend on vent come over and find him for me, but still I could not see the NPC.

Here is a screenshot of me looking at where Luquelot should be but is not visible or interact-able for me

http://i.imgur.com/RqAOJ5m.jpg

Also during this I noticed some people on mounts were also not visible.