Exactly the same for me. I do not use addons either. The crash on logoff started after the last festival patch but the game itself has no issue while playing. Also, sometimes closes very fast with crash report and sometimes hangs bad and needs a force closing. I do not have more than 8gb ram and this was no issue ever, not in GW2 or other games I play. My system is Win 7. I would never consider this a client side issue because the report we get at crash is too similar and our rigs are very different. I think among our reports are not 2 identical rigs. I know people always try to direct towards client side but this is not it. The ingame error screen and this logout crash issue appeared in the same time for me and straight after zephyrite patch.