@bmeeks :
Ok. So I disabled and unassigned the WAN Sort interface. Then copied it back to the newly unused WAN interface, enabled and started it and...... IT WORKED!!! I'm getting Alerts and its generating blocks as before the upgrade!

Same name as before, but apparently an internal interface mapping in Snort was still looking for the old WAN interface id.

Thanks!!!

UPDATE:

I've been doing some tests trying to know where the problem is and it seems that finally it comes from WAN interface. I configured first WAN but until I configured the IPSEC tunnels the problem didnt appear.

Today I reinstall a fresh pfsense and first of all I configured the tunnels with no problems and when I configured the WAN the problem start. If I enable WAN with DHCP or Static IP without a gateway it works everything fine, when I choose a IPv4 Upstream gatewy then return the problem.

At this point this topic can be closed.