[ic] process.html 404 errors

[Grant]

I'm running 5.6.2 and I get a fair number of process.html GET requests
that 404, but sometimes I get process.html POST requests (along with a
valid HTTP_REFERER) that hit special_pages/missing.html and 404.  Here
are a few UAs I've seen do this in the last few days:

(Linux; U; Android 1.6; en-us; T-Mobile myTouch 3G Build/DRC79)
AppleWebKit/528.5+ (KHTML, like Gecko) Version/3.1.2 Mobile
Safari/525.20.1
(Linux; U; Android 1.6; en-us; T-Mobile myTouch 3G Build/DMD64)
AppleWebKit/528.5+ (KHTML, like Gecko) Version/3.1.2 Mobile
Safari/525.20.1
Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_8; en-us)
AppleWebKit/531.21.8 (KHTML, like Gecko) Version/4.0.4
Safari/531.21.10

Examining the logs, they were obviously legitimate users.  Their
session changes on each page access, but their IP address is
consistent.  I can't figure out how this could happen.  Does anyone
have any ideas?

- Grant