Portenta H7 Ethernet module erratic behavior

Hi,
I have a strange behavior of 2 portenta H7 with a vision module including an ethernet module.
The 1st time I uploaded the openmv firmware V3.9.4 the network link was always down and the link led on the eth module off.
I downgrade it to the V3.8 and the network interface starts to work and I manage to get an ip address from the TCP stack and to connect to a NT server via UDP socket.
Then after a reboot of the H7 the network link was down and never came back up.
I can’t test the wifi with the 3.8 version because the timeout parameter was not accepted by the function wlan.connect(SSID, KEY, timeout=60000)

I reflash the portenta with the arduino firmware, the network module and the wifi module work perfectly.
I then reflash the openMV with the latest 3.9.4 from open MP firmware form the openMV website and flash the Portenta with the firmware from the portenta folder.
The ethernet and wifi start to work again. I then continue my development, next step was to connect MQTT via TLS encryption, everything was working well until one last reboot and then the network link went down again and since then never came back up. It is working fine though with the arduino IDE firmware.
This is very strange… The hardware seems to work fine because it is working with arduino firmware.
Has anybody encountered this problem ?
Thanks