For everyone out there stuck on "Crossing the Chasm" still - there is a valid workaround. This has been confirmed to work on the NA Megaservers twice already this morning but requires the co-operation of everyone on the quest.
If the East/West portals are not up and do not appear to be spawning, all players in that area go to the bridge that separates East and West.
Waiting there for approximately 5 minutes time, the portals then respawn. Everyone in the area can then rush the room, kill the mobs, wait for the portal to shut and get the update.
If players continue to stand near the portal room, in the room, run near it repeatedly - it blocks the portals. It appears to be some sort of proximity issue - the bridge is the safest bet for distance as again it has been confirmed twice to work around the blocking issue.