I've recently patched our distributed ISE cluster from 126.96.36.1998 (No Patch) to 188.8.131.528 (Patch 5).
Cluster consists of 2 x PAN, 2 x MNT, 4 x PSN all on physical SNS hardware.
I was playing with the idea of upgrading to 3.2.0, but I receive an error in a dialogue box when I browse to Administration --> System --> Upgrade.
"Previous upgrade is in progress for the deployment. Another upgrade cannot be performed until the upgrade process is completed on all the nodes in deployment"
I've tried restarting the ISE application and even did a reboot, but same story.