Yes i do have Airgroup enable too. Strange i tried to replicate the issue several times with iphone, ipad, macbook pro, and macbook air and clearpass show only 1 entry. Now it does not happen often but sometimes you look a user on the access tracker and have multple entries for some reason within seconds.
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It could be the client driver is aggresively sending a deauth to the AP and roaming to another AP within seconds and dauth again roam back to the AP. (This will cause the multiple entries in the access tracker because the client is indeed auth multiple times)
I am debugging the user in the controller and see if there is a dauth from the client or AP. I will update my findings.