Brilliant Tim!  A tremendous breakthrough 

Hi Lucas,

This looks to me like a bug in InterSystems FO generation.  You should contact the InterSystems WRC.

I see the following code in the FO:

<svg:link type="text/css" rel="stylesheet" id="dark-mode-general-link"  />
<svg:link type="text/css" rel="stylesheet" id="dark-mode-custom-link"  />
<!--  SVGStyle: %ZEN.SVGComponent.svgPage  -->
<!--  SVGStyle: %ZEN.Component.page  -->
<!--  SVGStyle: %DeepSee.UserPortal.standardPage  -->
<!--  SVGStyle: %DeepSee.UserPortal.DashboardViewer  -->
<!--  SVGDef: %ZEN.SVGComponent.svgPage  -->

While the comments are fine, the svg:link element should not be there.  Something else should be there instead.

HTML has a link elment and it looks like svg:link is supposed to be an HTML element, or maybe the generation for HTML intruded into the generation for PDF.

The following web page has the list of svg elements: https://developer.mozilla.org/en-US/docs/Web/SVG/Element.
.