Logo translating hack not working

I am using the TwentyTwenty theme and Polylang to run a site in english and french. But the design requires an english logo and a french logo.

Is this hack still supposed to work?

https://polylang.pro/a-multilingual-custom-header-image/

I have created the xml file and I do see the ‘custom_logo’ translation pair in the list of translations. I’ve put the media ID for the french logo in the box for the custom logo translation.

But no matter how many times I clear the server-side caching and refresh my browser, the logo is always the last one chosen in the customizer.

Whereas in the Customizer the site title and tagline — which are translated strings — switch between english and french depending on whether or not I’ve chosen english or french from the language menu in the admin bar.

The page I need help with: [log in to see the link]