I do not remember if I've reported this problem for 6.4.1 but it is still present with 6.5.0.

I've noticed that somehow access rights for /etc/net.cfg are reset to 0400. Experiments and investigation shows that 
it's io-pkt-hc run from enum-devices on boot that changes access rights. Currently I just work the problem arround by 
having chmod 644 /etc/net.cfg inserted in boot script after enum-devices, but it would be good to have the root of the 
problem fixed.