Okay, there were 2 Updates
Update 1: http://na.finalfantasyxiv.com/lodest...3df91dca352e8a
Quote Originally Posted by Update 1)
10/23/2013 2:09 AM
[Follow-up] Regarding Confirmed Issues With the Binding Coil of Bahamut – Turn 5 (Oct. 16): Follow Up 2
As you know, there are current issues with the Binding Coil of Bahamut – Turn 5 in which the monster becomes immobilized under certain circumstances, and as such, this challenge has been temporarily made unavailable to adventurers.

The issue has been confirmed during the final inspection phase and a fix is currently underway.

We are sorry for the wait. However, we do have plans to reopen the instance to players again sometime after tomorrow, so we ask that you please wait just a little longer. We will update you as soon as the reopening date has been confirmed.

We apologize for any inconvenience, and thank you for your patience.
Update 2: http://na.finalfantasyxiv.com/lodest...6f15d55eec56fe
Quote Originally Posted by Update 2
10/23/2013 4:08 AM
Planned Reopening for The Binding Coil of Bahamut – Turn 5 (Oct. 23)
The fix that was underway to resolve issues in the currently closed instance “The Binding Coil of Bahamut – Turn 5” has now concluded. We are pleased to announce that “The Binding Coil of Bahamut – Turn 5” is planned to reopen for challenge after the emergency maintenance that will take place from Oct. 23, 2013 11:00 p.m. to Oct. 24, 2013 2:00 a.m. (PDT).

We are sorry for the continued wait, and ask that you please wait just a little longer until the reopening tomorrow.

We apologize for any inconvenience, and thank you for your patience and understanding.