Created attachment 506 [details]
Error Message in Firewall Groups.

when adding a Firewall Group Network it will always Fail regardless of IP range use as long as you use the same Subnet as GREEN.

also same verification fails in IP Sec LAN-LAN Connection Setting. But there it only warns that the remote subnet is the same as the local Network and let you continue (LAN-LAN connectins still work)

Tested on upgraded installations, and fresh installations. 

no difference between i586 od x86_64

Replicate Error:

in Webconsole 

Firewall > Firewall Groups > Press on Networks
add dummy network with different IP range but same Subnetmask as GREEN.