Yes op, this is quite common. Had one last night where me and gnb (I was war) there was a short server wide lag spike near the end of p12n and all but us 3 died to the laser/line/chain to aoe explosion combo. We kept ourselves alive from 22% to 0 even with a vuln stack or two in the gnb case.

Let me just cut/paste something from my summary of healer issues thread

-The weapon's refrain and Epic of Alexander, have all been solo healed. Every other ultimate has been cleared without healers
-Eden's gate 4 (savage) was cleared without a healer when it was current content. https://youtu.be/zdDxjXMMWgU
-The 6.0 launch extreme trials have also been cleared without healers and with increasing frequency.
-Pandaemonium 1 normal was completed SOLO by 3 of the 4 tanks https://youtu.be/fFcZCEny4x4
-Pandaemonium 1 and 2 SAVAGE was completed WITHOUT healers when current https://www.youtube.com/watch?v=JRbvZJ-EU0U