I was having this problem consistently today. After reading through the above when I ran with apt-get update -o Acquire::http::No-Cache=True everything worked fine. As another datapoint, I know that our company recently installed a transparent http(s) proxy, so maybe there is something to do with the proxy response going on. I also ran with the debug output while it was failing and the log I got is attached.
I was having this problem consistently today. After reading through the above when I ran with apt-get update -o Acquire: :http:: No-Cache= True everything worked fine. As another datapoint, I know that our company recently installed a transparent http(s) proxy, so maybe there is something to do with the proxy response going on. I also ran with the debug output while it was failing and the log I got is attached.