After many attempts finally we found the solution. The EX switch uses the last IP address configured (vlan l3 or mgmt interfaces) as IP NAS origin. If you validate this attribute (the origin ip address) in your radius server, you must set this command in the EX switches in order to ensure the request is originated from IP address that you want.
set system radius-options attributes nas-ip-address [mgmt IP address]
For the first example the command is:
set system radius-options attributes nas-ip-address 10.10.10.10