Country flags/emoji not rendered correctly in some browsers

Iโ€™m building a personal webpage and want to use flag emojis. My default browser is Firefox and rendering this page there looks fine. However, flag emojis donโ€™t display correctly when doing the same in Chrome or Edge.

Below is the exemplary code snippet. Interestingly, the aeroplane emoji displays correctly in all browsers.

    st.write("Rolls-Royce :airplane: company with HQ in *Derby, UK* :UK:")

What may be a reason for such a behaviour? Is there a workaround?

:UK: is not a valid shortcode. Re emoji flags in chrome and edge, take a look at this chromium issue: