I have complained about this issue before. My wp-includes/class-http.php in my nigelweb.us site keeps giving me issues.
Every two days or so I have to upload a new one to the site because of issues I do not know.
I upgraded to the latest Wordpress install two days age and one day after that I realize I am still having the same issue. I do not have an answer for this but it is frustrating my clients.
When this happen, my whole multisite is down. Please Please Please take a look at it for me.
I extended support access to the site. Jack has all the information for my site access.