Duotone-Filter SVGs in HTML output below footer

I have the latest theme, GP Premium, and Generate Blocks plugins running with all other plugins disabled. On a server with no server caching and browser history cleared, every few page refreshes when exploring page source I find a list of zero pixel SVGs called into the HTML below the footer.

There are eight SVGs, each has a different filter:
<filter id="wp-duotone-dark-grayscale">
<filter id="wp-duotone-grayscale">
<filter id="wp-duotone-purple-yellow">
<filter id="wp-duotone-blue-red">
<filter id="wp-duotone-midnight">
<filter id="wp-duotone-magenta-yellow">
<filter id="wp-duotone-purple-green">
<filter id="wp-duotone-blue-orange">

All of this amounts to an additional 112 lines of code. What's causing this and how do we get rid of it? Thanks