At the edge of many ways, where previously in version 1.12 still fences (Fences) stood, are now after the update to version 1.13.1 only wooden sticks (wooden sticks) around. However, not all the fence was destroyed. Whether the fence is destroyed or not is not related to the type of wood.
It looks as if the player had died from a creeper explosion and dropped several stacks of fences. Partly the wooden sticks can be picked up and then found in the inventory, those that can not be picked up disappear by themselves when approached.