Hi,
i think your problem is that you have created a vlan "MGMT" with vlan-id 10 and then another vlan named "mgmt" (lower-case) which you have attached the vlan.10 interface:
vlans { MGMT { vlan-id 10; } mgmt { l3-interface vlan.10; }
Try to delete "vlan mgmt" and attach l3-interface to vlan MGMT :-)