How can deploy embedded form in Camunda standalone

I’m working on Camunda Standalone environment, I try to deploy one embedded form that from git call “camunda-example-invoice”.
I put the camunda-example-invoice.war under $TOMCAT_PATH/webapp/, when I launch the tomcat, it will not deploy into DB.
When I switch to Camunda prepackaged camunda-bpm-tomcat.war and do the same as above, it can deploy into DB and run the task.
Now switch back to Standalone environment, it also can see the form in tasklist page, but when click it will has error message: Form failure: The context path is either empty or not defined., and in browser developer mode the response is {"key":"embedded:app:forms/start-form.html","contextPath":null}.
Is it embedded form just can deploy into Camunda prepackaged environment instead of Standalone?