I've done quite a bit of ifrit lately and haven't noticed anything that would actually matter. I've seen plumes pop like that after Hellfire in your video but I wouldn't really call it a bug. It can be that the plumes go off when ifrit is near the middle and he walks over, while with latency it looks like he pops them under himself. If nothing else, it's fun when he does unpredictable stuff like that, not like the fight is broken or is any harder than usual.