I now installed version 4.9.0 with npm instead of the single executable. I could also remove the following setting:

"chrome": { "launchOptions": { "args": ["--no-sandbox"] } }

Now I see always 16 active processes since several days. So the problem is solved for me.

I have a similar problem. After some days we have about 300 chrome processes running.

We use the single file executable version of jsreport 4.8.0. It is configured as a service with NSSM. After a restart of the service, the processes dissapear. But after some days we have several hundred preocesses again.