conflict with mobile menu in safari/iphone

Hello! Love this plugin, but unfortunately it’s causing an issue with the theme I’m using for one of my new clients. Something in the slider is overlapping and therefore hiding the mobile menu specifically in safari and any browser on iphones.

You can see on the homepage: https://thememachine.com.au/ if you view on an iphone (all browsers) or desktop (safari only), when the mobile menu is activated (less than 980px wide) if you click to expand the menu, it opens but then is quickly covered up by blank whitespace. Whereas if you visit a page that does NOT have the testimonial slider on it (for example: https://thememachine.com.au/gallery/) – the mobile menu opens as it should.

I’ve disabled all other plugins and tested them one by one, it’s definitely Testimonial Slider causing the issue. Also, this issue does NOT occur in Android mobile devices or in Chrome and Firefox on PCs. It seems to be specifically an apple device conflict. it happens in both safari and chrome if viewing with an iPhone, and it happens only in Safari if viewing on a big screen.

I’ve already played around with z-index for several layers, but no luck yet. Any ideas or suggestions how to fix this? Any assistance is much appreciated!

The page I need help with: [log in to see the link]