This is something that I am currently puzzled about. Previous week I tried to keep full "rotation" up during both hero and eradication, and it was indeed annoying in terms of watching dot timer to make sure that no dots are clipping. And honestly I had a feeling that I am missing something, I guess a desire to nuke it was.

I wander if it worth trying to keep SB/Haunt(to refresh corruption and SE) only during Hero/Eradication (or DS/Haunt if it's below 25%), besides that, the proc rate of 2T7 is quite high so its bonus might be more useful in the current scenario?

I am going to try myself tomorrow, but would be interesting to hear from somebody who is running with 500+ haste on gear what do they think.

Edit: Formerly this was evidence in support of SE working for all locks, but after another round of tests with my aff lock pal, we have realized we're incorrect and SE is not working for everyone, just as has been stated. The initial tick increases we were seeing in our first casual test were smaller increases probably just due to Soul Siphon. To those who saw the post before, I still don't know how to explain how close our dot ticks were on the boss - that seemed to be the "true" evidence that with similar spell power we had almost identical dot ticks. But clearly that was due to other factors which would probably be explainable if researched enough. So, sorry for posting what ended up being a useless post. It's clear to me now that SE does not work for more than one person.

While testing we did figure out that they removed the old double-casting of drains to benefit from soul siphon, not sure if that has been reported/verified. Drain life not increasing second lock's drain life, same with drain soul, so drains are not benefiting from drains of the same name from any warlock.

The tests done on this might all be on target dummies. And maybe the bug only exist on those?

That's odd because in our guild you can tell who got the SE buff: Wow Web Stats - take a look at Luxury and Minarets

Note that Minarets was not glyphed for Immolate or Siphon Life. But if you take a look at our values:

Shadowbolt: 3882 vs 4129
Corruption: 1527 vs. 1812
UA: 1232 vs. 1475
CoA: 632 vs. 795

Our gear was about at the same level at the time, I've gotten quite a few upgrades since then. Maybe we should test on Dr. Boom?

Just did some tests with a fellow warlock, and the conclusion is; SE only benefits the player which applies it first.

We tested it in a live environment on mobs with approximately 12k hp, and we were both naked. We had the exact same amount of crit and a 1 SP difference.

Corruption ticks with no SE were 337 for both, 354 with 1xSE and 371 with 2xSE, and SE only benefited the warlock that applied the initial debuff.

However, we did notice some strange behaviour regarding "extra" ticks shown in the Blizzard SCT, showing additional ticks for about 44-47 damage. These did not show in in Recount nor the combat log, and they seemed to happen quite sporadically, thou always in conjunction with the Corruption ticks. Now I might be missing the obvious, but could someone care to explain what those ticks were ?

Pandemic maybe? Or pet attacks?

EDIT: Both of the above can be ruled out if your description of the situation is true. So that leads me to consider more obscure explanations:

Is there any way it could be Everlasting Affliction's 5% effect? What exactly was your spell power when doing this? (I realize you said you were naked, which to me would mean 0 SP, but I must be missing something, since you said you were within 1 SP of each other. At a random guess, maybe you had fel armor on?)

Nope, it was definitely not pandemic nor pet attacks. Pandemic would tick for 100% of the corruption ticks and show up in Recount as Pandemic anyways, this didn't show up anywhere at all except the blizzard combat text.

Fire Shield? 44 damage might be too much for that tho, dont really know how much it does.

Fire shield might be it, can't believe I didn't think of that. I didn't have my imp out but the other warlock did, so I'll just test it again.

Fire Shield sounds like a reasonable candidate. Not sure why it would tick for 44 (wowhead says max rank damage should be 33, and I doubt it scales with SP), nor why it would always coincide with a corruption tick. But the latter might be coincidence, and a variance in the damage of 10% could be explained by Molten Core procs.

Any chance you mistyped and meant about 34-37 damage?

Updated many parts of the main posts now, included many parts of Fallenmens Guide (thx for these). Corrected the spotted math errors. Actually I'm trying to improve the readability and include some missing pieces into the calculations (Like Drain Soul).