Ethernet device still disconnected after a 'link connected' log.

[Jean-Christian de Rivaz <jc eclis ch>]

In this observation NetworkManager still think that eth0 is disconnected 
while he correctly logged the message 'link connected':

Jul 27 07:46:24 x NetworkManager[2184]: <info> Activation (ppp0) 
successful, device activated.
Jul 27 08:20:09 x NetworkManager[2184]: <info> (eth0): link disconnected 
(deferring action for 4 seconds)
Jul 27 08:20:13 x NetworkManager[2184]: <info> (eth0): link disconnected 
(calling deferred action)
Jul 27 08:20:13 x NetworkManager[2184]: <info> (eth0): device state 
change: activated -> unavailable (reason 'carrier-changed') [100 20 40]
Jul 27 08:20:13 x NetworkManager[2184]: <info> (eth0): deactivating 
device (reason 'carrier-changed') [40]
Jul 27 08:20:13 x NetworkManager[2184]: <info> (eth0): canceled DHCP 
transaction, DHCP client pid 2270
Jul 27 08:20:13 x NetworkManager[2184]: <info> Policy set 'gsm1' (ppp0) 
as default for IPv4 routing and DNS.
Jul 27 12:59:30 x NetworkManager[2184]: <info> (eth0): link connected
Jul 27 12:59:30 x NetworkManager[2184]: <info> (eth0): device state 
change: unavailable -> disconnected (reason 'carrier-changed') [20 30 40]

root x:/home/x# nmcli d
DEVICE   TYPE      STATE         CONNECTION
ttyACM0  gsm       connected     gsm1
ppp0     unknown   connected     ppp0
eth0     ethernet  disconnected  --
lo       loopback  unmanaged     --
sit0     sit       unmanaged     --
wlan0    wifi      unmanaged     --

root x:/home/x# ethtool eth0
Settings for eth0:
    Supported ports: [ TP MII ]
    Supported link modes:   10baseT/Half 10baseT/Full
                            100baseT/Half 100baseT/Full
    Supported pause frame use: No
    Supports auto-negotiation: Yes
    Advertised link modes:  10baseT/Half 10baseT/Full
                            100baseT/Half 100baseT/Full
    Advertised pause frame use: No
    Advertised auto-negotiation: Yes
    Link partner advertised link modes:  10baseT/Half 10baseT/Full
                                         100baseT/Half 100baseT/Full
    Link partner advertised pause frame use: Symmetric
    Link partner advertised auto-negotiation: Yes
    Speed: 100Mb/s
    Duplex: Full
    Port: MII
    PHYAD: 1
    Transceiver: external
    Auto-negotiation: on
    Link detected: yes

root x:/home/x# nmcli  -v
nmcli tool, version 0.9.10.0

The state transition from 'unavailable' to 'disconnected' look rater 
strange or did I miss something ?

Jean-Christian