After lot of time spent on project I did realize that Color system do not work in Scene View, it updates only in Game Mode, and after exiting from playing mode drops back, and isPlaceable and !isPlaceable Tiles are displayed incorrect.
But I found decision to make it comfortable for me, and level building process became much better.
void SetLableColor()
{
if(gridManager == null){ return; }
Node node = gridManager.GetNode(coordinates);
if(node != null) {
if(!node.isWalkable){
label.color = blockedColor;
} else if(node.isPath){
label.color = pathColor;
} else if(node.isExplored){
label.color = exploredColor;
} else {
label.color = defaultColor;
}
} else {
if(tile.IsPlaceable == false){
label.color = blockedColor;
} else {
label.color = defaultColor;
}
}
}