Elements in the webpage is shown above / below one another based on their z-index.

So, in this case, it seems the sticky app has a higher z-index than your cart.

Follow these steps to fix it:

(1) Open the app > advanced tab > custom Javascript box:

document.querySelector('#cb-sticky').style.zIndex = "1";

(2) Open the app > advanced tab > custom CSS box:

#cb-sticky{

z-index: 1 !important;

}

(3) Save and test.