Main char it happens to is Zomega. The circumstances:
1) Get to character select and press "Play" as usual
2) Loading screen comes up with the name of the zone I am in (happens on different zones not just IC)
3) After a moment the loading screen vanishes and I am back to character select. It shows by character (a Zealot), except it is now showing up on the Order character select page. None of the other characters on the account are visible. The "Play" button has gone, but I can press the servers button to reconnect to the server again.
5) If I don't press anything then the screen eventually goes black
6) Usually gets stuck in a loop until I close and restart the client.
Has been happening on and off for weeks, getting more and more frequent as time goes on. It happened just now which is how I got the screenshots. My character was in Black Crag at the time of writing. I've managed to finally get in this time, but chances are it will happen again tomorrow.
This was not my first time in today either - I have been logged in for a lot of the day and had the same issues when first logging in this morning.
edit: I have also deleted cache, addons and all user settings (keybinding, stuff saved by addons, etc), to no avail.