Hi, sorry for the delayed response, without being able to replicate the issue it’s difficult to help - the menu works fine on multiple mobile devices here in the UK.
The best thing to do is to try to find what may be causing the issue, a few questions you might consider:
• Is it android or apple devices or both?
• Only on older phones or new phones?
• Is it using a specific browser causing the issue?
• Any extensions installed?
• Is something blocking javascript or is javascript not enabled on that browser?
• Mobile or wifi internet connection?
• Is that connection slow?
• Is it only a problem in your location? (In which case CDN location or IP may be causing an issue)
Also I noticed on your screen shots that the money converter app isn’t loaded yet, and on the second screen shot there appears to be a text box - what is the text box?