Problems with UPNP (miniupnp)

Hello

I have problems with upnp not working sometimes. Application in use is Transmission bittorrent client, observation is that sometimes the application is not able to open a port through upnp.

Transmission uses the miniupnp library, which also provides a test client, miniupnpc. Testing with this tool, RouterOs sometimes reports the external interface as not connected and sometimes as connected:

not connected:

Cancer:~ jacaru$ /usr/local/Cellar/miniupnpc/1.7.20120830/bin/upnpc -s
upnpc : miniupnpc library test client. (c) 2006-2012 Thomas Bernard
Go to http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
for more information.
List of UPNP devices found on the network :
 desc: http://192.168.1.1:2828/gateway.xml
 st: urn:schemas-upnp-org:device:InternetGatewayDevice:1

Found a (not connected?) IGD : http://192.168.1.1:2828/upnp/control/wanipconn-8
Trying to continue anyway
Local LAN ip address : 192.168.1.99
Connection Type : IP_Routed
Status : Disconnected, uptime=17982s, LastConnectionError : ERROR_NONE
  Time started : Tue Jan 15 16:34:12 2013
MaxBitRateDown : 10000000 bps (10.0 Mbps)   MaxBitRateUp 10000000 bps (10.0 Mbps)
ExternalIPAddress = 102.97.122.63
Bytes:   Sent: 91286639	Recv: 340976936
Packets: Sent:   324582	Recv:   416798

connected, shortly after for no apparent reason:

Cancer:~ jacaru$ /usr/local/Cellar/miniupnpc/1.7.20120830/bin/upnpc -s
upnpc : miniupnpc library test client. (c) 2006-2012 Thomas Bernard
Go to http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
for more information.
List of UPNP devices found on the network :
 desc: http://192.168.1.1:2828/gateway.xml
 st: urn:schemas-upnp-org:device:InternetGatewayDevice:1

Found valid IGD : http://192.168.1.1:2828/upnp/control/wanipconn-8
Local LAN ip address : 192.168.1.99
Connection Type : IP_Routed
Status : Connected, uptime=18173s, LastConnectionError : ERROR_NONE
  Time started : Tue Jan 15 16:34:12 2013
MaxBitRateDown : 10000000 bps (10.0 Mbps)   MaxBitRateUp 10000000 bps (10.0 Mbps)
ExternalIPAddress = 102.97.122.63
Bytes:   Sent: 97867929	Recv: 354574106
Packets: Sent:   340674	Recv:   435380

Of course, on both ocassions the external interface was connected and actively using it.

I user RouterOS 5.22, I have a pretty much standard configuration apart from vlan in wan interface and pppoe client over it.

[admin@MikroTik] /ip upnp> print
enabled: yes
allow-disable-external-interface: yes
show-dummy-rule: yes
[admin@MikroTik] /ip upnp> interfaces
[admin@MikroTik] /ip upnp interfaces> print
Flags: X - disabled 
 #   INTERFACE                            TYPE     FORCED-EXTERNAL-IP
 0   pppoe-out1                          external
 1   ether2-master-local              internal



[admin@MikroTik] /interface> print
Flags: D - dynamic, X - disabled, R - running, S - slave 
 #     NAME                                                                                                                                                                                                                             TYPE               MTU L2MTU  MAX-L2MTU
 0  R  ether1-gateway                                                                                                                                                                                                                   ether             1500  1598       4074
 1  R  ether2-master-local                                                                                                                                                                                                              ether             1500  1598       4074
 2     ether3-slave-local                                                                                                                                                                                                               ether             1500  1598       4074
 3     ether4-slave-local                                                                                                                                                                                                               ether             1500  1598       4074
 4  R  ether5-slave-local                                                                                                                                                                                                               ether             1500  1598       4074
 5  R  vlan6                                                                                                                                                                                                                            vlan              1500  1594
 6  R  vlan3                                                                                                                                                                                                                            vlan              1500  1594
 7  R  pppoe-out1                                                                                                                                                                                                                       pppoe-out         1480

Usually there is no problem when not connected is reported, but transmission is really pesky about this and refuses to open a port on this case.

Refer to:
https://forum.transmissionbt.com/viewtopic.php?f=2&t=13406
and
http://miniupnp.tuxfamily.org/forum/viewtopic.php?t=666

Any help?

BR