I use the password manager built-in to Safari on OSX (which synchronizes via iCloud), and the names of the form fields on the "change password" page really confuse it such that it has no idea how to fill things out. For example:

  • "New email address" (form item emailpwnewemail) becomes blank
  • "Retype email address" (form item emailpwcheckemail) gets my username
  • "New password" (form item emailpwnewpw) gets my old password
  • "Retype new password" (form item emailpwcheckpw) triggers Safari's "generate a new password" thing, which then gets duplicated into the "Password" entry in "in order to verify your identity" (form item emailpwpw)

I suspect the combination of weird form entry names as well as the atypical order of the entries is confusing to Safari's password manager, and likely confusing to many other password managers as well. Of all the sites I use, Weasyl is the only one with this particular problem. I suspect that putting the "verify your identity" block first would fix this issue, although changing the form IDs to something a bit more logical/likely (e.g. username, oldpassword, newpassword, newpasswordcheck, email, emailcheck, where the names have meaningful and unambiguous prefixes) would probably also help.