I have no idea if this is related, but it is a weird thing that happened immediately after the downtime.

I usually log in without the "remember me" box checked. So I logged in as usual, got the usual "thank you for logging in" message, and when I tried to do something such as replying to a post that would require me to be logged in, it told me "you have to be logged in to do that". I am NOT talking about after enough time had passed for my login to have timed out, I am talking about only seconds after logging in.

So I tried logging in with the "remember me" box checked, and it worked fine. Later, after I had logged out, the next time I logged in, I did not check the box and it worked fine. Have not had a problem since.