CSS being downloaded twice

Question

I was inspecting the network tab in Chrome, and I saw that some CSS files are being downloaded twice. I don't know why, but just the ones from a CDN (I don't know if it's the problem, I just noted it).

I'm not using a Service Worker to control it, and it's only included once in my HTML (when I click to see what line is calling the file, both files point to the same line).

Here's a screenshot:

Here's the HTML:

<link rel="stylesheet" crossorigin="anonymous" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u">
<link rel="stylesheet" crossorigin="anonymous" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" integrity="sha384-wvfXpqpZZVQGK6TAh5PVlGOfQNHSoD2xbE+QkPxCAFlNEevoEH3Sl0sibVcOQVnN">
<link rel="stylesheet" crossorigin="anonymous" href="https://cdnjs.cloudflare.com/ajax/libs/admin-lte/2.3.11/css/alt/AdminLTE-without-plugins.min.css" integrity="sha384-WG5KI+rc1FCbcov6sW97p+sxrnYctXfkPWh+TtV+NHpIW2/svd8GC7v/PFFATsCh">
<link rel="stylesheet" crossorigin="anonymous" href="https://cdnjs.cloudflare.com/ajax/libs/admin-lte/2.3.11/css/skins/skin-blue.min.css" integrity="sha384-HpPw4BJmJc5KUoRUqCQwYKo0Kk94VbzanZQdGrG0m5h2dnUTxN0FHRDmKNyv5ymR">
<link rel="stylesheet" href="https://infomec.net.br/assets/css/main.css?v=2.8">

The same happens in the incognito mode.

You can visit https://infomec.net.br and inspect it (login: stackuser, pass: stackuser; just created this user for it).

I would love any help, trick, or direction to look, since I've already done a lot of researches but nothing has worked.

Chrome 56.0.2924.87 (64-bit), Windows 10 (Version 1607, build 14393.693)

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EDIT

What I tried:

Disabled any Chrome extension - Same thing

Disabled asynchronously download of 2 CSS files, they were being downloaded only once, now they're being downloaded twice too.

Removed integrity from links - WORKS!, but... why?

So, I just inspected it using Edge, and...

... same issue, but it shows that one is being downloaded by XMLHttpRequest... why?

Answer 1

Try removing the integrity keyword from the CDN and check if it works. For me it is working on removing it. The problem might be because of many reasons some of them being your extensions installed, your browser version etc.