Reviewing the Jaspersoft logs, entries like this are found:
2018-08-07 17:01:18,351 ERROR CsrfGuard,https-openssl-nio-x.x.x.x-x-exec-1:44 [x|x] - potential cross-site request forgery (CSRF) attack thwarted (user:<anonymous>, ip:x.x.x.x, method:POST, uri:/x, error:required token is missing from the request)