Runtime Field Intermittently Working?

I've configured a runtime field in Kibana 8.7.1 under index template and named it drive.used

emit(doc['drive.capacity'].value - doc[''].value)

However, looking in Discover, the field doesn't always show up:


What am I doing wrong here?

@wwalker It might be easier to iterate on a runtime field defined in a data view. Based on what I see, its possible that you're pulling data from different indices only some of which are impacted by the index template.