Getting very slow ajax responses when requesting product page

Question

I'm building a Chrome extension for the steam community, and this extension has some functions to get the user games list and scrap their product page to get some information about every game.

Any of the requests done by the extension to the API is almost instant, but when I try to load an app page (like for example http://store.steampowered.com/app/440/ ), the response is delayed up to 40s.

At the end, the page loads and the ajax request is successful, but the waiting times are just too high.

I have noticed that this behaviour is not consistent, and on other computers with the same exact extension code and internet connection theresponse is instant, and on the same computer with other browsers the delay is not there either.

Why could this happen? I'm not starting multiple ajax calls, and the extension waits before finishing a call before making the next one.

Please, see attached image

Thanks