Force reset position of actor after snapping to the ground. Otherwise

the interpolation calculation would kick in and make the actor goes upward if the
spawn point is higher than summoner or downward if lower. The actor
would then either jump or fall through terrain.

apps/openmw/mwworld/worldimp.cpp

@@ -1351,6 +1351,8 @@ namespace MWWorld
         }
 
         moveObject(ptr, ptr.getCell(), pos.x(), pos.y(), pos.z());
+        if (force) // force physics to use the new position
+            mPhysics->getActor(ptr)->resetPosition();
     }
 
     void World::fixPosition()