Two Identity Profile Problems
For years I have been able to have open two Identity Profiles in Firefox. One for my wife and one for me so we can have our own Yahoo and Facebook accounts open at the same time on one computer. With in the last couple of weeks it will log me out of both Yahoo & Facebook accounts on Profile 2 but Profile 1 continues to stay logged in. Every time I relogin to my accounts on Profile 2 within about a minute or two Facebook will tell me "Your not logged in" and close me out and my Yahoo account will rest to the sign in screen.
Opaite Mbohovái (1)
You could try checking your proxy setting in Profile 2. Definitely Yahoo is sensitive to this. Please see the following thread: I am able to log in to Yahoo mail but it keeps asking me for my password every 2 or 3 mins.
Does it help?