'No roam-track information exists for the station' on HP850

[tdeserranno]

'dis wlan client roam-track mac-address' displays 'No roam-track information exists for the station'  for clients connected to  service-template 2 as configured below :

wlan service-template 2 crypto
 ssid SSID2
 bind WLAN-ESS 2
 cipher-suite wep104
 wep default-key 1 wep104 raw-key cipher xxxx
 client forwarding-mode local vlan 2
 service-template enable
#

interface WLAN-ESS2
 port link-type hybrid
 undo port hybrid vlan 1
 port hybrid vlan 2 untagged
 port hybrid pvid vlan 2

 mac-vlan enable
 port-security synchronization enable
 port-security port-mode mac-authentication
#

For clients connected to service-template 4, I do get roam-track info (though the connected client hasn't roamed yet)

-------------------------------------------------------------------------------
 BSSID          Online-time(d:h:m:s) AC-IP-address
-------------------------------------------------------------------------------
 4431-92a3-03e1 0002:06:20:56        192.168.255.99 (HOME AC)
-------------------------------------------------------------------------------

wlan service-template 4 crypto
 ssid Intern
 bind WLAN-ESS 4
 cipher-suite ccmp
 security-ie rsn
 client forwarding-mode local vlan 67
 service-template enable

#

interface WLAN-ESS4
 port link-type hybrid
 undo port hybrid vlan 1
 port hybrid vlan 67 untagged
 port hybrid pvid vlan 67
 mac-vlan enable
 port-security synchronization enable
 port-security port-mode userlogin-secure-ext
 port-security tx-key-type 11key
 undo dot1x handshake
 undo dot1x multicast-trigger
#

What makes that one service profile gives roaming info while the other doesn't