Hi Carinaa,
Still no luck, I even installed the copy I have with the bug fixes and it’s not working. But one thing I found, your site doesn’t use cornerstone-endpoint, and the requests are different. Please check these screenshots
The working one on my install,
And the one on your site
The one your site is parsed as content-disposition instead of actual JSON data. This means, the data being passed is multitype with different size ranges, in other words, splitting it depending on the sizing of content position, hence the data being sent may not able to reach the server especially if it contains large data in which invalidated the byte range. https://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html. You can also compare from the screenshots the content-type, the correct one is JSON type and not multi-part. The multi-part is usually utilized for file attachments and emails.
This is not builder issue since the builder only has JSON type for Ajax requests, the cornerstone-endpoint is even omitted by something.
Could you try this on another host? I’m not saying you should move, but just to test it, because it’s not happening on any of my setups even with large items of The Grid.
Thanks!