[xyclos]

> It has a number of URLs. I suppose it's possible at least one of the URLs is no longer legitimate

Just a guess, but since it is a file which lists website urls one of those domains was probably flagged as a phishing site, and since your doc had a url with the same domain it got flagged as well. It wouldn't surprise me to find that one of those candidates' sites had actually been hijacked by some phisher. Unfortunately just visiting each site wouldn't necessarily reveal which one it was since they'd likely have tucked the php shell or other phishing stuff at some path away from the root of the site to avoid detection from the site's maintainer.