Web site caching problem

I've noticed this on my iPad since the upgrade to iOS 5, but just noticed it on my iPhone for the first time today...

A lot of times when I'm reading a web page and press the back button, I'll be taken to a previously cached version of that page, from eariler in the day or the day before.

For instance, it's something I see a lot on a forum, or a link aggregator like Reddit. I'll click a link, hit back, and then end up at an out-of-date version of the page.

Anybody else having this problem?