This is just an issue in the HTML for that dropdown. The flag pack the project uses is flag-icon-css, this uses https://www.iso.org/obp/ui/#search to get country 2 letter identifiers for the various flags. If you inspect the Irish flag in the running app "flag-icon-ir" (which is for Iran) is used instead of "flag-icon-ie" (Ireland).
This is just an issue in the HTML for that dropdown. The flag pack the project uses is flag-icon-css, this uses https://www.iso.org/obp/ui/#search to get country 2 letter identifiers for the various flags. If you inspect the Irish flag in the running app "flag-icon-ir" (which is for Iran) is used instead of "flag-icon-ie" (Ireland).