PageBuilder Image Field not saving value

I have a content type with a custom field, defined in the form.xml

The image uploads as expected using a Controller.
However when I save the page where the content-type is, the field value is not saved. What am I missing here?

    <fieldset name="general" sortOrder="20">
        <settings>
            <label/>
        </settings>

        <field name="entity_id" formElement="input">
            <settings>
                <dataType>int</dataType>
                <visible>false</visible>
            </settings>
        </field>

        <field name="image">
            <argument name="data" xsi:type="array">
                <item name="config" xsi:type="array">
                    <item name="label" xsi:type="string" translate="true">Image</item>
                    <item name="formElement" xsi:type="string">imageUploader</item>
                    <item name="dataScope" xsi:type="string">image</item>
                    <item name="visible" xsi:type="boolean">true</item>
                    <item name="required" xsi:type="boolean">true</item>
                    <item name="dataType" xsi:type="string">string</item>
                    <item name="sortOrder" xsi:type="number">10</item>
                    <item name="source" xsi:type="string">page</item>
                    <item name="uploaderConfig" xsi:type="array">
                        <item name="url" xsi:type="url" path="Vendor_Module/image/upload"/>
                    </item>
                </item>
            </argument>
            <settings>
                <dataScope>image</dataScope>
                <validation>
                    <rule name="required-entry" xsi:type="boolean">true</rule>
                </validation>
            </settings>
        </field>
    </fieldset>