Two of our iOS apps broke because of this bug. This is a huge breaking issue. Two known workaround: 1.) appending random query value to the request URL and 2.) update the web service to set "Cache-Control: no-cache" in the response headers for POST requests (perhaps this affects PUT and DELETE requests as well).
Ran into the same issue today. I'm really surprised that Apple went down this path, as I can only imagine the havoc that it will have wreaked across the web. I know that it's caused some serious issues in our app.
I'm also wondering why this change wasn't announced to developers by Apple more clearly -- I can't find any mention of it in the release notes. [1]
The random query value is probably the best solution. We have had this in our app for years, because it has been an issue in both java and IE for a long time.
