node process recurrent locks in production, urgent!

Please provide the following details if possible or relevant:

- [1.1.1] the version of Ace impacted by the issue (as returned by the `ace -v` command).
- [8.8.1.0] the version of Node used to run Ace (as returned by the `node -v` command).
- [Windows 2008 R2] your operating system and version.
- [no log file as process locked] if the issue is a bug when running Ace: the error message as produced in the log file (you can enable debug logging with the `--verbose` option).
- [] if the issue is about the HTML report: the browser(s) and version(s) you used.
- [] if possible, let us know if you can share a sample input file to help us reproduce the issue.

Using Ace from the command line on the production server, there are recurrent locks of the node.exe process, at least once a day.
Our team has to kill the process for next validations to run on following EPUBs.
Attached is the screenshot of node.exe process stopped.


Any clue or checks we should try to figure out what's going wrong ?