WLC 2504 with LAG

Question

Hi all.
I`m configuring new 2504. I updated it to 7.4.100.60 and enabled LAG.
I want to configure interfaces "ap-mgmt" - for AP management.
(Cisco Controller) >config interface create ap-mgmt 69
(Cisco Controller) >config interface address dynamic-interface ap-mgmt 10.50.50.157 255.255.255.224 10.50.50.158
(Cisco Controller) >config interface ap-manager ap-mgmt enable
AP manager interface already exist on port.
So I disable ap-manager on default "management" interfase and enable it on dynamic "ap-mgmt"
(Cisco Controller) >config interface ap-manager management disable
Warning!  You have no AP manager on this port.
The controller behavior will be unpredictable.
Are you sure you want to continue? (y/n) y
(Cisco Controller) >config interface ap-manager ap-mgmt enable
After that I have nice sh int summ, I can ping all interfaces, but AP can`t register on the controller "ap-mgmt" (10.50.50.157) interface
(Cisco Controller) >show interface summary
Number of Interfaces.......................... 5 (<-- I don`t understand why 5 shown here)
Interface Name                   Port Vlan Id  IP Address      Type    Ap Mgr Guest
ap-mgmt                          LAG  69       10.50.50.157    Dynamic Yes    No  
management                       LAG  79       10.10.10.95     Static  No     No  
virtual                          N/A  N/A      1.1.1.1         Static  No     No  
workstations_wifi                LAG  74       10.200.200.253  Dynamic No     No
After reboot
(Cisco Controller) >save config
Are you sure you want to save? (y/n) y
Configuration Saved!
(Cisco Controller) >reset system
Are you sure you would like to reset the system? (y/N) y
System will now restart!
I got this:
(Cisco Controller) >show interface summary
Number of Interfaces.......................... 5
Interface Name                   Port Vlan Id  IP Address      Type    Ap Mgr Guest
ap-mgmt                          -    69       10.50.50.157    Dynamic Yes    No  
management                       LAG  79       10.10.10.95     Static  Yes    No  
virtual                          N/A  N/A      1.1.1.1         Static  No     No  
workstations_wifi                LAG  74       10.200.200.253  Dynamic No     No  
(Cisco Controller) >show interface detailed ap-mgmt
Interface Name................................... ap-mgmt
MAC Address...................................... fc:99:47:1b:77:60
IP Address....................................... 10.50.50.157
IP Netmask....................................... 255.255.255.224
IP Gateway....................................... 10.50.50.158
External NAT IP State............................ Disabled
External NAT IP Address.......................... 0.0.0.0
VLAN............................................. 69       
NAS-Identifier................................... wlc2504-1
Active Physical Port............................. Unconfigured
Primary Physical Port............................ Unconfigured
Backup Physical Port............................. Unconfigured
DHCP Proxy Mode.................................. Global
Primary DHCP Server.............................. Unconfigured
Secondary DHCP Server............................ Unconfigured
DHCP Option 82................................... Disabled
ACL.............................................. Unconfigured
mDNS Profile Name................................ Unconfigured
AP Manager....................................... Yes
Guest Interface.................................. No
L2 Multicast..................................... Enabled
(Cisco Controller) >show interface detailed management
Interface Name................................... management
MAC Address...................................... fc:99:47:1b:77:6f
IP Address....................................... 10.10.10.95
IP Netmask....................................... 255.255.255.0
IP Gateway....................................... 10.10.10.254
External NAT IP State............................ Disabled
External NAT IP Address.......................... 0.0.0.0
VLAN............................................. 79       
Quarantine-vlan.................................. 0
Active Physical Port............................. LAG (13)
Primary Physical Port............................ LAG (13)
Backup Physical Port............................. Unconfigured
DHCP Proxy Mode.................................. Global
Primary DHCP Server.............................. Unconfigured
Secondary DHCP Server............................ Unconfigured
DHCP Option 82................................... Disabled
ACL.............................................. Unconfigured
mDNS Profile Name................................ Unconfigured
AP Manager....................................... Yes
Guest Interface.................................. No
L2 Multicast..................................... Disabled
So my newly created "ap-mgmt" interface was thrown from LAG and default "management" interface was restored as AP Manager.
After reboot I can`t ping "ap-mgmt" (10.50.50.157), it`s clear why - because it have no physical port associated with it.
My question is why I can`t make other than default "management" interface as AP Manager when LAG enabled?
I try 7.4.100.60, try 7.4.100.0, try two more 2504 results the same.

Answer 1

>it's recommended to put both of them into the same VLAN and the same subnetIn documentation I don`t find such recommendation, please share the link.
And it states:
AP-Manager Interface Configuring the AP-manager interface on the same VLAN or IP subnet as the management interface results in optimum access point association.