GetNearest and SingleNodeBlocker

Hi,
Im using a simple code to get the nearest walkable point the AI will reach to mellee attack the player in a turn based grid graph. Im trying to use GetNearest but it always finds the same node as the targets.

This is the code:
GraphNode nearestNode = AstarPath.active.GetNearest(destinationVector3, NNConstraint.Default).node;

I found out That the nearestNode is considered walkable but there is a gameobject with SingleNodeBlocker. I have checked that when I try to go around the object with SingleNodeBlocker I do.
Tx for help

Hi, any idea, anyone?