Hi,
Ok, I found the issue which was totally my fault. The loop was not creating nodes continually and caused unreachable target.
Regarding the sparse option, and the distance to connection, I am still not able to enable it. I will keep it disabled, not sure about its benefits.
Note that I did not find any method to reset all the nodes inside the graph, as a workaround, I am calling Scan without any GO which seems to clean up stuff, after what I can add all my nodes/connections.
Best