You are right. It behaves like that.
We will ship the fix in the next full jsreport hotfix. In a few days.
Until then, you can apply config useExtensionsLocationCache: false, as a workaround.
const jsreport = require('jsreport')({
useExtensionsLocationCache: false,
extensions: {
express: { app: reportingApp, server: server },
},
appPath: "/reporting"
});
I apologize for the troubles.