A couple fixes have been pushed through that should hopefully make these more accurate. The most important fix is that if you change guilds, it should now be updated properly. Remember that the armory has to first update a guild change before we will notice it. It may take up to 24 hours before the fixes fully propagate through as we need to get your latest guild information again.
Also, just a heads up for those who aren't aware. The Armory seems to be having issues updating arena teams. If this is affecting your access, please shoot me a PM with a screenshot of your character tab. Based on that and your gear information, we can usually manually grant you access.