I have one of the bindings of the windseeker in my bags but for some reason ATT isn't registering that I have it. I've tried reinstalling the addon but it didn't seem to help. I saw something about deleting the cache but I wasn't sure if that my Warcraft cache or some add on cache value.

ATT does not track inventory, it tracks completion. You need both bindings for Thunderfury, so it will continue to say 0/1 on both until you've done so. If you expand the binding in MC, you'll see that that is why it shows up.