Ok, so Elegon is down. Ugly down, we (barely) won. So I feed the log to the analyzer and I find that I suck (hardly a surprise), but also that there is a phase where Elegon is DoT-immune (I had not really cared much to check, it seems to be during the p2-p1 transitions, from a cursory look).
But there's stuff going wrong: I have a BitW range which starts in phase 1, which is definitely wrong. Looking at the visualization it seems like there's a Rip which is lasting too long. I know that 1 extra tick is possible, but here it's more than that. Usually, even when one extra tick is added, the aura fades immediately afterwards, but here it seems like there's a refresh after half a tick, and this with 4 extra ticks. Since visualization is independent of the preprocessing, it means that there really is some spell_periodic_damage going on. I'll have to go through the log in detail to see what happens. Blizzard does weird stuff with the logs at times (and not just logs...) :).