Hi,
I have checked and it seems that the DOM elements related to GTranslate are not there until you click on the language icon, which then initializes the GTranslate related content, but it looks like the order of the initialization is messed up, so it does not work.
My recommendation is to let the elements initialize on load and not on popup open.
Alternatively you can use our paid version which will be fine, because it does not need to load js libraries from Google.
Thanks! 🙂