I agree this is not an SG issue. I was getting the problem and had never joined a SG on any of my toons. This issue never occurred until the release of the Halloween patch, that is the exact day that it started. What is also very telling is that if I do a /reloadgfx when I enter a mish the problem goes away until I re-enter a zone affected by the Halloween events. Then I can /reloadgfx until my fingers bleed and nothing changes until I enter a non-Halloween area again.