Cached web pages are the source of many problems with browsing from a mobile phone. The problem is often caused by getting the device to market quickly, so many corners are cut and so many odd behaviours get introduced.
Apple do their best to adhere to standards but even they too make the odd mistake.
Designing web sites that work on both normal screens and small screens is challenging enough without having to also deal with issues introduced from the phone manufacturers. If trying another browser doesn't work then you may want to let the web admin of the site know there is a problem with the page which could have a Time To Live (TTL) set too high. Some phones handle this disasterously if used regardless of its value.