As reported here and here, I am having some kind of issue when trying to use import scripts or the "add cluster as release" plugin while using the beta site. First I was getting a login prompt, and then that was ok but I was having the trouble with artist search.
What's really odd is that once I hit "Stop using beta site" once, then I can switch back to beta and it seems to keep working. But I've also seen the login problem reoccur, under unclear circumstances. (I thought maybe it was restarting the browser, but at least that alone hasn't done anything.)
If it matters, I'm using Chrome.