I just picked up the same one as you with the same output. I believe you will need a second license based on this example as a fully licensed 6450.Is this what the 10G port adder license looks like? so 2 base + 2 from the license?
Index Lic Mode Lic Name Lid/Serial No Lic Type Status Lic Period Lic Capacity
Stack unit 1:
1 Node Lock ICX6450-10G-LIC-POD dbtF<snip> Normal Active Unlimited 2