Communication on Different VLAN IDs on Cisco vs Juniper

Hi Guys,

I have different VLANs on Juniper EX4200 and Cisco 6509 and they are connected via access port. All my ports are access( switch to switch and switch to servers).

Servers in different VLANs are able to reach each other. Any one can explain this behavior please ?

Swtich to switch link configurations:

Cisco 6509

interface GigabitEthernet1/48
 description to JNPR_es_4200_ge-0/0/38
 switchport
 switchport access vlan 10
 switchport mode access
 no cdp enable
end
------------------------------------------
show run vlan 10
Building configuration...

Current configuration:
!
vlan 10
 name TEST_10
end

Juniper EX4200

show configuration interfaces ge-0/0/38
description to_csco_6509:gi1/48;
unit 0 {
    family ethernet-switching {
        vlan {
            members 20
------------------------------------------>>> show configuration vlans | match 20 | display set
set vlans TEST vlan-id 20

Thanks