I think that this is caused by number 2. The date is 2015/05/12 at 12:14am central time.
I'm using Firefox version 37.0.2 on Ubuntu 14.04. Please let me know if you need more information in tracking down this bug or if you want me to test something.
P.S. Tried it on Chromium Version 41.0.2272.76 Ubuntu 14.04 (64-bit), but didn't get the CSRF page. Instead, the Rove beetles link took me to the forums webpage (http://www.permies.com/forums). Hope that helps.
"The problem is with the "/permaculture-forums" part. The post rendering part of the forum software doesn't recognize this this part, so it tries to 'fix' it by adding a /forums suffix. Which means "www.permies.com/permaculture-forums" gets 'fixed' as "www.permies.com/forums/permaculture-forums", which breaks things down.
I've never seen a permies URL with /permaculture-forums format before - maybe it was an old URL format? "