If you request a password-reset email using an email address, we now also recognise your website username from the part before the @. The reset mail still goes to the email address currently stored on your member record. A send that actually fails is reported as an error, instead of looking as if it succeeded.
If that stored address is a committee inbox mailbox, we do not send the reset there. You are asked for your membership number and home postcode, then a personal email you can read without signing in, and the reset link goes to that address.