Multi language site "Add additional guest" not working

[dan-chaya]

Hi

I'm building a website which supports two languages (German and French). The plugin is used so that guests can subscribe to a marriage (hence, it's the same event in both languages). Unfortunately, the button to "Add additional guest" only works in German. (There, it shows the fields to add an additional guest.) In French, the click subscribes the as clicking on the regular "RSVP" button. No additional fields are shown.
I've checked if there is an issue with the javascript function, but I couldn't figure out the reason it bugs. It seems to be correct as far as I see. So, there isn't any input that I can provide this time around.
Otherwise, the plugin works great as people can RSVP in either language. So, it's just that additional feature that isn't working properly...

Best regards