Exstream File write operation

Exstream is generating PDFs in a single directory, while a script simultaneously copies these PDFs to another directory.
When the script is not running, Exstream can write files to the disk without any issues.
However, when the script starts running, it affects the file-writing process from Exstream, causing most jobs to be queued in the output queue.
Do you have any ideas on resolving this issue from the Exstream side?