Marshallers are calling disconnect every time a process is persisted. Once we call this method, the current ProcessManager removes the persisted instance from memory.

If a Async work item handler is trying to use that manager to complete a work item when the future task is completed, it will fail because it want be able to find the process instance, something that did not happen when persistence is not active

For reference:
https://github.com/kiegroup/kogito-runtimes/blob/master/jbpm/jbpm-flow/src/main/java/org/kie/kogito/process/impl/marshalling/ProcessInstanceMarshaller.java#L89