I need help with an issue of megamenu 7 on Safari only on iphone (it works fine on other browsers and devices).

The issue is quite simple: we do not use responsive toggle menu, we have just the same menu on mobile, but with vertical submenu.
With the latest version of megamenu for drupal 7 the submenu does not display anymore on iphone, while it works fine on ipad. This issue does not happen with the older version of megamenu 7.

I cannot post the links to see this issue for privacy reason. Please contact me in private. Thanks :-)