Hi,
The function checkInfiniteScroll check whether you're and the bottom of the page, and if you are, it loads the next batch of products through AJAX.
If you refresh the page, then the browser asks again to the server to load the page and in that case, the server replies back with the first batch of products. That's normal, that it works like that.
There is no function to load again all the products loaded before the page refresh. That data isn't stored anywhere on the browser by HikaShop.
Now maybe firefox has some kind of caching and when you refresh the page, it actually doesn't refresh it but use its cached version.
Or maybe does it tries to scroll down to the position where it was and in the process, it triggers the AJAX loading of the additional products.