I know the recent change to map files was supposed to have caused all the bad pathing of mobs being pulled into walls and agroing the whole zone and I know it's been reversed... it's definitely better than it was yesterday but it's still worse than it was before the initial change.
Some mobs still wall and fall through the world where none did at all before.
Often this happens when you're carefully drawing the mob back to camp, yet it steams off into a wall at right angles and disappears, bringing half the zone with it soon after (or disappearing for ages and then warping to you ages later).
Something's still up. Worst offenders are the wurms. The other big give-away is the pathing around the hub, where before drakes used to just follow you in a direct line off the top (if you dropped down) but now they resolutely follow a path all around the top of the hub, then down the stairs.
Now, this ain't so bad but it's an indication that ToV has not been reversed; the mobs never did this before, until yesterday and they're still doing it now.