Hi, the way you described your code the behavior is expected this is because handles are kept track of internally in memory by a particular instance of the MS Excel VBO. They are not shared between instances of the VBO. In your case, the instance of the MS Excel VBO that holds the handle for the instance of Excel you're attempting to interact with is purged from memory at the end of the process.
your assumption itself is correct, but you might want to consider a slight re-design to your processes. It's unlikely that the optimal design of a given Blue Prism process would open an instance of Excel in one process, and not interact with it until another process.