Disconnects are huge problem since U39. I take the time to write what was going on in the crash reports, but it doesn't matter what your doing. Just standing around you disconnect, using bank you disconnect, zoning out/in you disconnect, fighting group boss you disconnect....it just doesn't matter what you're doing since U39.
And of course I've gone through the trouble shooting crash report links Bill has provided multiple times. There is something significant going wrong on the server side.