CloudFront closes connection

We have a ASP.Net MVC 3 legacy CMS application. This application serves resized images to CloudFront as a Custom Origin. Most requests are fine and either the cache is hit or the image can be retrieved from the CMS application. It has come to our attention that on some of the request the following HttpException occurs:

The remote host closed the connection. The error code is 0x800704CD.

This error occurs while the server is trying to flush the output stream.

The following headers are being sent before the output stream is flushed:

Content-Type: image/jpeg
Content-Length: 142475
Content-Disposition: attachment; filename=banner.jpg

The issue is not bound to the file. It seems to randomly occur on all kinds of files and is also size independent.

I already tried searching for this issue and couldn't find anything specific on it. I just wanted to check if anyone has some experience with these issues on CloudFront.