Polylang and random header image

Thanks for Polylang.

I stumbled upon this: With polylang, the custom header image:

add_theme_support( 'custom-header' );

in functions.php the header image

get_header_image();

only works with one language if several header images are uploaded and set to random. With the other language, get_header_image() returns an empty string.

With only one header image set, it works fine.

https://www.ads-software.com/plugins/polylang/