insertListing is making 2 ajax calls and one of them is causing 500 error

I am loading up a customer grid into a modal with insertListing:

<insertListing name="customer_listing">
                <settings>
                    <dataLinks>
                        <exports>false</exports>
                        <imports>true</imports>
                    </dataLinks>
                    <autoRender>true</autoRender>
                    <selectionsProvider>
                        customer_listing.customer_listing.customer_columns.ids
                    </selectionsProvider>
                    <dataScope>customer_listing</dataScope>
                    <ns>customer_listing</ns>
                </settings>
            </insertListing>

This makes the ajax call and the JSON is returned, but then it seems to make a second ajax call to :

admin/mui/index/render/key/8614a3119e77f668213d6ff33014e71a0b87731972324c882736b1d4a61e0724/?isAjax=true

With this payload:

namespace=customer_listing&filters%5Bplaceholder%5D=true&search=&paging%5BnotLimits%5D=1&form_key=7Owtqwtb1kf4jGR1

The problem is this second call just causes a 500 error and i have no distinct error in any logs explaining why. The weird thing is if i just go to the normal customer listing screen this doesn’t happen

UPDATE

The issue seems to be in vendor/magento/module-ui/Controller/Adminhtml/Index/Render.php

This line of code is causing it:

$this->getResponse()->appendBody((string)$component->render());