On a lot of websites after you log in once, your iPhone asks if you would like to save your username and password credentials for future logins. Ease of Access I should say.
Every time, It pops up on one of my three woltlab installations, I press the username to autofill and both boxes stay blank. Woltlab this is the only instance I have not had my info auto-filled. I was just curious if this was a bug.