MPSK ARUBA-UNIFI Pre-SHARED Keys

I have a unifi network we are chaning over to Aruba. It is a School and soon to be at all the buidlings in the District. The Aruba and Unifi have the exact same network name. Unifi using the pre-shared keys and Aruba is using the mpsk files with roles. I am finding that devices that roam from one side of the building to a portion that has the other brand installed we have to delete the network and reconnect and then it is fine. This only seems to happen if a staff member goes from one side of the building to the other where one half is one brand aps and the other side is the other brand. Does anyone know why? I have a feeling it is something to do with the mpsk file and was trying to find out how unifi works in the backend with the pre-shared keys.