it still happens in launcher version 1.3.8 - Minecraft version 1.7.4
This is not fixed. Or it returned. I am running on 1.2.1 and this exact bug is happening. And it is not related to MCL 602, let alone duplicated. 602 is about switching profiles (maybe offline<->online)
I am using two online mode accounts, they act as stated in this issue, the first one is getting logged out.
Edit: Oh, I didn't know I actually CAN update / add the affected version number(s)
okay at least now we know. could you make it configurable so devs can actually test things on online servers with multiple accounts?