As the title says, leading and trailing white space make the login not recognize accounts. I stumbled across this one when I let my browser auto-fill my e-mail address and didn't realize it put a space at the end of it. After some frustration of thinking I forgot my password, I went to the recovery option only to find it said I didn't have an account with that e-mail. It of course worked fine once I found and removed the extra space at the end, so I wouldn't call this a major issue by any means.
