Coils of Bahamut... and its inconsistent challenge level.

[Vidu]

No it quite literally broke it, and stranded us there.

Where you able to reproduce the error?

Because right now I'd heavly assume that its a technical error, that would need technical looking into - something that needs to be fixed, so the content can once again work as intended.
I did T11 a few weeks ago (we didnt cleared it because people didnt know mechanics and after telling one person to stand out of the baro-field 5 times and they still stood in there, I had it with this group and trying to explain) and even though our adds merged aswell, we still got to see Kalia perform her nerve gas/cloud, a raid-wide AoE that used to wipe you if didnt kill the adds in time - it still happens even if you do kill the adds, but it deals less damage then.

So I see two options here right now:
1) There was a bug that happend for some specific reason (because two things that shouldnt come together came together or something like that) - that would need looking into. Intresting here would be of the question: Can this bug be reproduced? As in: is it something that always/very often happen?
2) There was no problem except you missunderstanding something of the fight - I could actually imagine something along the lines of you expecting the adds merging would wipe you immidiatly; you felt you couldnt deal damage to the add anymore (if you werent close to it, that might actually be the case, its a mechanic, there is a buff for that on the add) and because the timer took so long to run out you assumed something was broken.
So... did the adds disappear before you gave up? Did Kalia casted nerve gas/cloud? Were you able to target her after that?