First, see the expected behavior by visiting
Next, from the same browser, visit
The issue appears to be specific to 302 redirects from .mobi domains. Webkit properly ignores viewport settings for pages on .mobi domains, but on iOS this behavior is also applied to any pages that are arrived at via a redirect from a .mobi domain.
See also: bug 97556.
I noticed this behavior with .co domains with a 302 redirect with iOS7 safari.
Maybe it is applied to all 302 redirects.
iOS bugs should be filed at bugreport.apple.com