Sorry about this hassle. It does look like we may even be breaking Pinterest’s login form too.
Yes, it applies directly to the site, sorry that isn’t clearer. (I’ve added a note to us to fix this.)
I want to test this to get it fixed, but I can’t find where to get the bookmarklet, could you possibly send me a link of where you got the bookmarklet from? (Or some pointers of how I might do so when I’m logged in.)