diff --git a/apps/openmw/mwworld/scene.cpp b/apps/openmw/mwworld/scene.cpp
index 87234408d6..7e3a00df07 100644
--- a/apps/openmw/mwworld/scene.cpp
+++ b/apps/openmw/mwworld/scene.cpp
@@ -543,6 +543,8 @@ namespace MWWorld
 
     void Scene::changeCellGrid(const osg::Vec3f& pos, ESM::ExteriorCellLocation playerCellIndex, bool changeEvent)
     {
+        mHalfGridSize
+            = isEsm4Ext(playerCellIndex.mWorldspace) ? Constants::ESM4CellGridRadius : Constants::CellGridRadius;
         auto navigatorUpdateGuard = mNavigator.makeUpdateGuard();
         int playerCellX = playerCellIndex.mX;
         int playerCellY = playerCellIndex.mY;