Hi,
It must be because of the jquery conflict. I need to see our website and check the console logs.Please provide me your website URL to let me browse.
But you can try this:
The .chosen() plugin is usually causing the conflict (between jQuery and MooTools). You should disable it from VM backend.
Navigate to Joomla Backend >> VM Configuration >> Template and find this option: Use jQuery chosen for dropdowns in FE and disable it.
Regards