I solved this issue using this post: https://community.jaspersoft.com/knowledgebase/how-to/accessing-jsqueryjs-custom-ui-pages-starting-jasperreports-server-v800/
Starting with JasperReports® Server v8.0.0 the libraries used by JasperReports® Server will not be exposed to the global scope.
We are using jquery in the javascript accessed by the CVC. Therefore, jquery needed to be installed in the scripts directory on the server. Then needed to add this script tag to decoratorMinimalImports.jsp file:
<script src="${pageContext.request.contextPath}/scripts/jquery.js"></script>