Thankfully, I managed to find a quick fix for this problem. Just two lines of code that prevents the page from scrolling to the top when you click that Reply button.
Here's how to fix it:In your blog template, search for this code:
replyParent = commentId;
Then, right after that line, paste this code:
var x = document.getElementById(commentId);
Save your template and the problem should be fixed now.