When using the Views Module, I found that I would be thrown JSON data when I attempted to make changes to fields. The changes would still be made, but a white screen full of JSON data would populate the screen. I eventually realized that the external iframe module was throwing an error (length is null?) in the console and after removing the module completely did the Views Module work fine.

I am uncertain if this is a Views Module error or an External Iframe error. The Views module has had this issue before but there seems to have been a fix made for it so I am uncertain as to why External Iframe brings the issue back up.

If this issue does not belong here, I apologize.