Subprocess restrictions
All activity nodes can be used in a subprocess except a SubProcess node. If a SubProcess node is used inside a SubProcess node, there will be a process error in the Designer as well as a runtime error.
All process variables from a subprocess will be copied over to the main process while it is running. Therefore, any start variables defined in a subprocess will also be start variables for the main process and will be available to all nodes in the main process. If more than two subprocesses have the same start variable, only one start variable will be copied over to the main process. For example, if subprocess1 and subprocess 2 both have the same start variable called "test", only one of the start variables will be copied to the main process. The other start variable will be lost. Therefore, do not use the same start variables in subprocesses that will be used in a common process.