i just upgraded from 3.2.3 to 3.2.8 and had the problem, that my process variables was not found anymore. After some debugging, I found out that the HashCode of my root token changed during execution because I set the ProcessInstance.key property during process execution as soon as I know my unique business key. The changes hashcode and equals for ProcessInstance and therefore also for Token.
I think this is a major bug! At least it changes the behavoiur of existing processes. What do you think?