Post editor loads empty

I am running WordPress 3.8 and I recently switched server, so didn’t realize when the problem creep in but most likely its the server change and I need some help figuring it out.

When I open post edit screen, the editor is empty. Switching context in Visual / Text happens but as if the editor is totally empty. There are no JS errors either.

Two things that I see happening:

1) The edit page screen always show this message when moving away from it or closing it, as if there is some pending request awaiting completion.

2) There are weird characters in a post output now. This is happening for a lot of posts.

If I dump the post content using get_post(), its shows up fine without any weird characters.

Also if I dump the database and import on my local, everything works just fine. So I think there is some issue with the server only, perhaps a charset encoding issue?

Ruled out any plugin causing it by disabling all plugins.

Also not sure if its related, but there was some issue with concatenation of scripts and I had to add define('CONCATENATE_SCRIPTS', false ); to make scripts load correctly.

I am not sure where to look. Any ideas?