Hi Johnny,

This is expected as multi-select is not supported in non-template mode.

You can try  below work around to implement your requirement:

1.create a TestUpperSection wrapper section, and make it non-auto(i.e in HTML tab uncheck Auto-generated HTML checkbox)

2. add below code 

<%

   pzAuto.getUIComponentRuntime().resetTemplatingUIStatus('Y');

%>

<pega:include name="TestSection" type="Rule-HTML-Section"/>  //TestSection contains multiselect control for custom filtering

3. save the rule.

4. Goto report definition -> Report Viewer Tab,

5. in Display custom section inline area , for Name change the name to wrapper section i.e change TestSection to TestUpperSection

Hope it helps.

Thanks.