I've checked this ticket and confirmed the issue happened on lucee latest version 5.3.8.180-SNAPSHOT also.

• Using Fusionreactor, the Stream metric shows 3 flushes for a template. In ACF It uses one flush for a template.

• Lucee included a formtag-form.cfm file in the script tag for every CFFORM tag. For the first cfform tag, it included in the head tag after that it included at before form tag in the body tag of the HTML.
  https://github.com/lucee/extension-form/blob/master/source/java/src/org/lucee/extension/form/tag/Form.java#L469
  it should be cached and include once as per request.

• The form-tag.cfm file doesn't cache by the browser. Seems, In ACF cfform.js file was cached by the browser.