Upgrade to 2.5.0pl Cannot Save Existing Template

Greetings,

I've just updated a development site to 2.5.0, after I had completed the update I went to edit one of the existing templates that were in the install before the update and I get an infinite loop on save.

On looking at the console i get this error: Uncaught TypeError: Cannot read property '1' of null

I'm using uncompressed JS on Chrome: Version 51.0.2704.106 m

I tried the same site on Firefox and had the same version, and I do not know how to correct it. I can create and save NEW templates, but not edit old ones. I have no issues saving resources, its only on the templates. I have uninstalled CodeMirror and disabled all Template Variables that are for the page and im currently at a blank

Any advice?

Thanks