JQuery Sizzle attributes being added from one server

Question

I have read the other questions and answers regarding what Sizzle is and what the attributes it adds to elements are, but none of them answer the question of why its happening.

I have the following setup:

HTML5 codebase using JQuery 1.10.2.

3 webservers with the same code deployed to each.

IE11, Chrome, Safari and Firefox.

On Chrome, Safari and Firefox the website looks identical when served from all three servers.

On IE11, the website looks identical when served from two of the three servers.

The difference between IE11 with the content served from the two working servers and the one non-working server is that in the developer tools I see all of these Sizzle attributes on objects - but I cannot for the life of me work out whats causing it, why it would be different and why only on IE on one of the three servers.

Any ideas?

Answer 1

And solved it - IE was set to view "intranet sites" in IE compatibility mode for whatever reason Microsoft decided.