I had a problem with my MFA recently. LastPass stopped asking me for it. I looked and my Yubikey was still registered, it just seemed to be ignoring it. So, I added a new MFA target (Google Authenticator) and it started asking me for MFA again, that's the good news.
However, now whenever I open the browser it takes me straight to the MFA dialog, bypassing the login. If I put in my MFA token it logs me in. This seems weird, but it gets weirder. If the browser has many windows open (and I always have many windows open) it puts the MFA token login in many windows (not all, not sure why it does some and not others). The problem is that if I switch the browser to one of the other windows with MFA open, and just close the window (because I logged in on another window), it logs me out of LastPass. WTF? Closing an MFA when logged in, logs me out? This makes no sense.
Better yet, when I login in one window it should close all the other MFA windows (or it should open the MFA in its own window). I did see others complaining that they are still logged-in on the browser after closing the browser, and I agree that this should be a configuration option, so this might actually be about this (I would want it to log out when closing the browser).
The MFA problem is really annoying. It means that every time I open the browser I have to look at all windows and close all MFA tabs before logging in, then I still have to login (and get yet another MFA window).