That is something I hadn't considered actually. I usually keep my camera zoomed out as far as it'll go (I play a tauren, I need the distance), and just select targets with tab for AoE trash unless there's a priority target, so I'm not always sure what mob in a pack I'm hitting. One more thing to watch out for next time then.

Well I would be care on testing this too much in a large AOE pack environment unless the mobs have a lot of hitpoints because on things like the spiders in naxx, everything dies so quickly that it is possibly dead(when you factor in instance lag + normal latency) yet still showing alive on your screen which could explain another possible cause of missing 1 or 2 prongs on your chain lightning. As it stands most of these type of packs are dead before the cooldown on my original chain lightning is up.

Now if you are AOEing deathknight packs or something it is worth watching, and paying attention to your target if they are spaced out by any relative measure.

I would honestly be surprised to see chain lightning being broken. If a spell has always worked(not counting lightning overload) and always works outside of an instance, I see no possible explanation other than latency and other possible causes mentioned in the threads above for causing these discrepancies.

I had been ignoring the CL bug reports, but decided tonight to test on a whim.

I am doing Naxx military Q as I type this, on the DK packs mentioned, and something IS wrong with CL. Sometimes the 3rd jump just is not happening. Other times it is, but the dmg of the 3rd jump is taking 1sec+ to appear. Its not happening everytime, and I can't see the common factor, but it is definitely not working 100%.

I've noticed this for a while now, as well. I haven't done any reliable testing yet, but I think it's related to positioning.

Suppose the letters below indicate the mobs positions and the numbers indicate the order the chain lightning should jump. I believe the third jump doesn't happen because the mob is on the far side from where the second jump is.

The CL is cast on mob B, then jumps to mob C. Instead of jumping back across B to hit mob A, it just stops.
However, if the mobs are in the same position with the CLs hitting in the order as below, the CL would hit all three.

Yeah that is the graphica representation of what I explained 2 posts back.

Mootimus is this the case or is it something entirely different? Is Naxxramus lagging at all for you?

It could be that the latency of the server is cutting off the final bounce of Chain Lightning because the spell because it doesn't have time to make 2 distance calculations in the minumum time that blizzard sets on the server side for a spell to complete or something obscur like that.

What would really be interesting to see would be the Chain Lightning Glyph testing to see if this is cutting off both the third and 4th jumps during this or not.

When I saw the bugs it varied, but at points I was stood ~30y away from a tightly packed group of mobs, being AOE tanked together. Latency was quite low by current standards. So, I actually think this is a genuine bug. At times there were 4+ mobs in the group, so it should have found something to hit.

The positioning bug doesn't quite make sense to me anyway. I understand if something is way off to the side, but I have certainly never noticed it failing to jump relatively short distances before.

I don't know whether lag is really the issue behind the missing CL jump, but I can confirm that abilities get "skipped" due to server lag. We've just had a large amount of people migrate here and I've seen this happen a few times (i.e. a DK with the appropriate talent not switching into ghoul form at all).

edit: I've had the bug occur with very low latency, so I'd tend to say that it's in the mechanic itself and not connected to lag.

But you need to pay close attention in what order the mobs are standing in and what your primary cast target is.
If you think when a tank has mobs on him, in controlling them they usually form into a semi-circle around the tank of about 30-40 degrees or so. Depending on which mob you tab to, he can be in a different "place in line"(being far left is at the front of the line, where the right mob is the back)

If you get unlucky with the description I gave you can get unlucky CL's. I have this happen to me much more often has a healer casting Chain Heal, as the "chain" mechanic is shared and I do a lot more Chain Healing than u can cast Chain lightning. :P If a chain heal jump goes into a melee that is around people with full health, it won't jump again. Situations arise where I unsuspectingly cast CH on a melee near the "back of the line." The CH jumps from that melee to another at the extreme left or right side of the boss. Since CL and CH cannot go to the same target twice, it cannot make the range check required to jump, so it doesn't.

To determine if this is a real issue or not very precise tests would need to be conducted to see if the configuration of the mobs can make this issue occur or if it is simply "bad luck", or lag as someone else posted.

I am not shouting about this, as its a fairly inconsequential issue in terms of my main concern in PVE. However, something odd was and is happening. I have done enough soloing and general playing of Ele to see CL jump in some very generous ways in the past. At best we can say its now being much stricter, at worst its outright bugged.

There has been a fairly regularly bumped post on the EU Shaman forum about this. Whilst anecdotes are of course only of so much use, I do believe something is off here.

I can confirm the observation but with a caveat. In Naxx last night my opening CL on the spider packs was truncated to 1 jump rather than 2 most of the time ... I did not keep an exact count but I would say 3 of 4 times. I know the mobs were there, and in range and tightly packed, so it is not a position issue ... nor would lag directly effect it as they were tightly packed before and after the cast went off. While my group is pretty good, they are not good enough to knock off a spider in the pack fast enough for the intended jump target to die before the jump could occur on my opening cast. LoL, at least not through AoE alone.

The caveat here is pretty bad lag - it might be the cause of the issue. In fact I would guess that it is. I will try to test this by running a few 5 mans early in the day before the lag monster rears it's ugly head.

Yesterday in Naxx, I attacked a small spider mob before our mages could get to it and observed the same thing. I had changed my Combat Log filtering to only show events done by me to confirm it wasnt an issue with MSBT. My CL only was shown to hit two of the ~7 spiders with no one else attacking them (Except the DK who had dropped D&D).

To top it off, the CL proc'd LO, which again only was shown to hit two targets.

Obviously, one cannot tell if it's just an event issue with the raw combat log, or if CL is actually only hitting two targets in a large mob of available targets. I know I have no issue with CL sleeping on the job in 5mans or the rest of Naxx when the pool of available targets is much smaller.

I've seen the same issue repeatedly using default UI, but again only in Naxxramas. I wonder if the issue will persist after the performance upgrades supposedly in the pipes.

The bug is probably a carryover from its previous functionality. Before the CD wouldn't start until the buff was used (or removed) in order to prevent someone from being able to use it twice consecutively. It's likely that the continuation of this behavior is an oversight.

You shouldn't be afraid to post bugs like this to the EU forums. You won't get a reply from GC, but it's not like Blizzard gave you forums so they could ignore them.

Another Shaman here chiming in with anecdotal reports of Chain Lightning only jumping to one additional target. The behavior has been noticed by myself (Ele shaman) and two other Shaman I run frequently with (another Ele, one Enh).

It's most noticeable in the spider wing of Naxxramas, for obvious reasons: very tightly grouped mobs in large packs, with no obvious reason why the Chain would only jump once. I plan on testing the Chain Lightning glyph next time my Shaman is in a raid, but that likely won't happen until Sunday/Monday. One thing I'm wondering that I'd love to test is if there's a possible z-axis issue with the jumps. I've noticed that in areas like the spider wing (lots of ramps and varying heights in combat) and the Sarthareon trash (hilly terrain) CL only seems to hit two targets per cast, yet on a fight like Sarthareon proper (fighting on a flat, level platform) my CL is easily able to hit three targets per cast if they're available, even when the targets are more spread out. Alternatively, there could be an issue with the second jump being unable to hit a target too close to the first jump, which could also cause the behavior we've seen.

Running Sarthareon trash right now:

Chain Lightning, and LO Chain Lightning, are definitely only jumping once. Both myself and an Enh Shaman are watching it and are only seeing the first jump, regardless of proximity or order (ABC/123 example a few posts ago). With Glyph of Chain Lightning, CL/LOCL gets an additional second jump, but not a third.

We're convinced something is wrong with the CL jumps, just have no clue what triggers it.

I can confirm that. It struck me doing trash in Naxx while using a new addon (MikScrollingBattleText) that merges the CL jumps to one number like "CL: 8322 (2 Hits)". Although there always were more than enough targets in range to jump to, I almost never got a CL with 3 Hits.

I'm curious to hear if anyone is still experiencing this issue with CL in Naxx after 3.0.8. We did our run tonight, and I noticed on the spiders that I was once again hitting 3 mobs according to the UI.

Yep, we trying Sartarion and i see 3 targets hits with my CL now (before 3.0.8 - always only 2, always)