Regular & strange behavior EP socket response ?

I’m very pertubate.
I’m using xbee.getnodelist() to list all ep (7)
only the 3 first can be reach without problem. But the strange thing, these 3 are 1) in the same place than 4 others (less 3 meters), 2) and these 3 goods EP are not on the minimum distance to the router ?
I ’ dont know why ???
Someone could help me ?
Best regards.

Which XBee products are you working with?