Lavastorm Near Najena entrance
 

Outside the tunnel to Najena entrance there is a large area where mobs fall under the ground ( world ) you can see the mobs pathing then they disappear and fall under.. my pet fought a few under there, it's looks like a pretty huge area.. just fyi

err make that all of Lavastorm !

Can you be more specific? Which mobs? Where exactly?

saw fire drakes doing it all over lavastorm today

All the mobs that roam. My pet also fell through near the Druid ring and got stuck under the world. Fire Drakes , Rock Dervishes, Lava Crawlers, after hunting there a bit longer I noticed the Mobs pathing through the peaks and mountains not over them.. in a lot of place they will fall through the ground.. there were about 5-6 mobs I couldn't loot today. I think this might affect the whole zone. I saw it everywhere I went and I covered a lot of ground.

Very strange. I have a theory, but I have to look into it