Got this first time ever last night while loading an old unpublished project in the foundry editor, it bounced me all the way back to the loading screen suggesting I submit a ticket. I simply relogged and the error never reoccurred.
Switching between characters results in a
"Got Duplicate LOGIN_SUCCESS".
I got the same, and my first thought was concern over my account being compromised. I got no email alerts and it only happened once. Since I was able to immediately re-login, I think it's more likely a glitch related to LoR.