You can do the following step to reproduce with the following config.

ezpublish:
    siteaccess:
        match:
            Compound\LogicalAnd:
                - matchers:
                        Map\Host:
                            www.host.com: true
                        Map\URI:
                            ww: true
                    match: siteaccess_ww

1°/ include a legacy template in a twig one :

2°/ load this template through a sub-request with strategy ESI
3°/ use ezurl in the legacy template

The url generated by the template operator ezurl should be prefixed by /ww, but they are not.

If you change the matching to URIElement, the generated url are fine.