Metadata: Setting epubAccessibilityConformsTo by script / Missing export to EPUB metadata?

Hi everyone,

I've tried setting the value for epubAccessibilityConformsTo to "EPUB Accessibility 1.1 - WCAG 2.1 Level AA", but I can't seem to get it quite right:

function setEPUBAccessibilityPreferences(){           
    with(app.activeDocument.epubExportPreferences){	
	epubAccessibilityConformsTo = "EPUB Accessibility 1.1 - WCAG 2.1 Level AA"
	epubAccessibilityCertifiedBy = "Certifier"
	epubAccessibilityCredentials = "Credentials"
	epubAccessibilityReportLink = "www.report.link"
	}
};

Is there any official documentation for which (string) values are allowed for epubAccessibilityConformsTo?

I've only been able to find the unofficial InDesign ExtendScript API Adobe InDesign 2025 (20.0.0.95) Object Model - EPubExportPreference reference which does not give information beyond stating that epubAccessibilityConformsTo takes a string value.

When I try 

function setEPUBAccessibilityPreferences(){           
    with(app.activeDocument.epubExportPreferences){	
	epubAccessibilityConformsTo = "EPUB Accessibility 1.1 - WCAG 2.1 Level AA"	
	epubAccessibilityCertifiedBy = "Certifier"
	epubAccessibilityCredentials = "Credentials"
	epubAccessibilityReportLink = "www.report.link"
	}
	alert(app.activeDocument.epubExportPreferences.epubAccessibilityConformsTo)
};

it correctly shows "EPUB Accessibility 1.1 - WCAG 2.1 Level AA" in the Script Alert.

When opening the EPUB export dialogue after running the script, nothing shows in the Conforms To field. I'm using the German version of ID, so it's the field labeled "Entspricht:" in the attached screenshot.

Also, I noticed that the EPUB3 metadata after export will not contain 

<meta property="dcterms:conformsTo">EPUB Accessibility 1.1 - WCAG 2.0 Level AA</meta>

but only show

	<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
		...
		<!--accessibility options-->
		<meta property="a11y:certifiedBy">Certifier</meta>
		<meta property="a11y:certifierCredential">Credentials</meta>
		<link rel="a11y:certifierReport" href="www.report.link" />
	</metadata>

 even if I manually select "EPUB Accessibility 1.1 - WCAG 2.1 Level AA" from the dropdown menu.

At this point, I suspect there is something amiss with ID processing the value for the Conforms To dropdown - has anyone here encountered this issue, too?