reset password fails, sends 2 one-time login link emails

reset password fails at save password & log in screen, then it loads Reset password form repeatedly.

This happens on only one D7 migration site, not on another, nor on the newer sites originally from BD.

So creating new account fails at the one-time login link step. Possibly related, when the one-time login link email is sent, 2 emails are sent, identical except for the one-time login link is different. I think this is the problem since the system won't allow 2 different links or clicking more than once.