I am not sure what to say about the underline thing, although I have noticed the occasional post with it. I will try and be more observant the next time I see one.
The auto log in is controlled on your computer. Perhaps you have a new one, or a new/updated browser, or increased your security settings. What it is, is when you click the "remember me", a cookie is placed in your computer so that when you come back, the site recognizes you and loads your relative information.
Probably check your security setting first. Maybe settings on some kind of "safe web surfing" program.