I use 1Password to manage my logins around the web. I'd have well over 200 Logins stored, so I'm no noob.
However on the two occasions* that I've tried to create a Stack Exchange account and clicked on 1P's Password Generator function the Stack Exchange form validation returned a "Passwords do not match" error.
I've never seen this on any other website.
*On neither attempt have I received the confirmation email that I was informed I had been sent (it's been 24 hours since my first attempt and, yes, I checked my spam filter)