Subprocess Variables: Child process variables lost

I am currently using the Flowable UI Free Version 6.8.0 and have encountered an issue related to subprocess variables. The problem arises when invoking a Call Activity subprocess within the main process. Upon completion of the Call Activity, any variables associated with the subprocess seem to be lost or inaccessible.

This becomes particularly problematic when we need to resume the main process and refer back to the exact task that triggered the Call Activity subprocess. Without the preserved subprocess variables, it becomes difficult to maintain the necessary context and effectively continue the flow of the process.

What is the history level of both subprocesses? Or if not set, what is the global history level?

use in/out parameters of call activity.