it seems that when I make vegitation, I can't make anything in the level layer. Meanwhile making overgrowth, I did minor things in the level layer such as changing road position and relocation of 1 building. After packing map, such error appeared at 15%:
However when I clicked "cancel", the map loaded. There was overgrowth which I made, but the road was in the previous position. But the building was in the correct place...
So what should I do? I opened editor again and the road is in the correct place, I just moved a little bit the spline just to save changes, but it didn't help...