Loading iframes shouldn’t automatically add to browser history. You could search for occurrences of history.pushState to see if the code is explicitly adding to history.

As a hack, if your code executes before history is altered, you could do something like

let oldLength = history.length;

// go back to previous page
$(document).on('click', '.back', function () {
    let currentLength = history.length;
    window.history.go(oldLength - currentLength - 1);
});

It sounds weird, but I have a back button that use JS method window.history.back(), all I want is to go back to the previews page. I noticed, when I click to see the customer’s detail page, where my “back button” exist, if I click before loading the entire document, the button works OK,I mean, just one click, and it returns to the page I was before. But if I wait until the documento is full downloaded, it icludes 3 iframes , then I have to click on the “back button”, 4 times to return one page.
This is the button code:

<a class='btn back pull-right' style='background-color: #45B6AF;color:#ffffff;'>Back</a>

I use the class back, and this is the JS part (extenal js file):

// go back to previous page
$(document).on('click', '.back', function () {
window.history.back();

});

Any ideas, I have been with this for two days !!!