Just wanted to correct a mistake I made above, I just doubled checked the error I was/am getting - it is a 403 error (forbidden) when the admin-ajax.php file tries to load up the following script at:
wp-admin/load-scripts.php?c=0&load%5B%5D=jquery-core,jquery-migrate,utils,json2&ver=3.9.1:4
The problem seems to happen when a page is "reloaded" or part of a page is reloaded. For the first 10 or so calls to file everything seems fine, and the data is returned fine, then it starts returning the 403 error. :(