Our guild has been running into some seriously ridiculous bugs with these bosses. Below are a list of the ones we'e encountered, most of which have been reported since as early as PTS, still with no fix.
*Stormcaller drops lightning spears on melee during initial phase, even when there is a ranged close to the tank and further away
*Defensive system shell doesn't spawn
*Invisible lightning spears (no indication of it dropping either, you just start taking damage)
*Lightning spears drop INSIDE the defensive system on stormcaller's side, even when the tank is right outside dropping them like normal. (basically the lightning spear mechanics of both phases are active at the same time).
That last one was happening to us repeatedly last night and we had to call the raid. Every attempt, the defensive system would just fill up with lightning spears even WHILE i'm dropping spears outside of the defensive system (i'm the tank). We've killed them several times, are executing the strat flawlessly and are dying to stupid bugs that cause an instant wipe.
This is seriously getting ridiculous -.-
Not sure what your raid comp is but you should run it with only one ranged on firebrand standing on the ground (prefferably someone with a cure..mercs are great for this). Everyone else on both sides should be in melee range of the tanks. This should prevent the spike from being dropped on the melee. The only time you MIGHT get a spike on melee here would be during a tank swap. Seen it happen once. Group just had to shift over slightly.
Invisible spikes usually only happen at the beginning of the fight if you just zoned into the area after a wipe for example. Ground effects dont load immediately. This isnt the only fight in the game with this issue. Whoever is on the ground just needs to know when the spikes come. (After the first missle thing firebrand does right after you engage the fight). After the first one drops the rest should be visible.
By defense system shell I take it you mean the sniper bubble? I have never seen this bug before. Not sure what you could do about that if it kept happening other than resetting the instance. Also if your bringing anyone new make sure they know not to AoE at all.
I cant comment on the spikes the tank drops during the barrage phases since ive never had to do that. I think it goes by agro though so if the tank dies the spikes shift to someone else.