Relative urls - browser plugin? scraper? other?

I have a very strange situation that I’ve been tracking for some
months now.

This may or may not be a rails issue. The symptoms don’t feel like it,
so I guess I’m appealing to my rails colleagues to lend me their
thoughts.

Throughout the day, HomeStars.com will get a number of invalid
requests(< 50) such as :

/companies/1199238-action-assembly/forums - is not valid

/companies/1199238-action-assembly - is valid
/forums - is valid

/forums is linked to in the menu on each page (so is /sessions/new
which also exhibits the same behaviour)

All I can surmise is that something is hitting the forums relative url
thinking it’s relative, but it’s an absolute reference.

Forum

So this feels like either a bug in a scraper, or a page pre-loader
(plugin that visits links on a page to pre-load them).

I see enough of them, with differing user agents, and vastly different
IPs, and not enough requests to not feel like a scraper.

So I’m left with thinking it’s a browser plugin - pre-loading.

any thoughts or pointers are appreciated.

thank you.
Jodi