There must be something sitting between you and our server which is trashing the urls. We don't do any rewriting at the domain level as the site supports multiple different domains - so if you start on canalplan.org.uk then you stay on it. No-one else seems to be reporting problems to us either through here or Facebook or Twitter and we've had 41 PDF routes generated today. If you can send me your IP address via Private message I'll dig into the server logs and bug reports to see if I can see anything obvious.
I did notice something very odd - that authentication token is for user 23 Users of 90 and below were only used for Beta testing and were discarded. Current users IDs are in the mid 2550s Auth tokens like that are send in the User account confirmation email and are a one use token which is never used again once we've confirmed that the account request is genuine. After that you login on the front page using user ID or Social App auth. Logins are not needed to plan routes, download PDFs etc - they are only needed for things like submitting data updates or photos. or saving planned routes so you can reload them, or reporting bugs or using the simple forum system.