Recently the following exception has been showing up in the log when clicking around the demo (and especially, but not necessarily, on the About page, which is displaying a video). It seems to happen when the video is being loaded, but no longer when it's cached. (Using a new private session in a different browser seems to trigger it reliably.) It may have to do with MTE-93. By adding controls automatically to video components, we may have made browsers try to fetch the video more aggressively. Below is the short version of the exception. Attached are the longer version (when log level is set to debug), and a similar exception pointed by fgrilli, from MAGNOLIA-3855.

2016-11-18 11:45:14,426 INFO  info.magnolia.dam.core.download.DamDownloadServlet: Download of document [grca-over15-432.mp4]was interrupted due: java.io.IOException: Broken pipe:java.io.IOException: Broken pipe. To see more details change logging level to debug.
org.apache.catalina.connector.ClientAbortException: java.io.IOException: Broken pipe