That is not how sites and stuff do it, usually when you are using a new password they show two fields on the same screen; i wasn't expecting it to ask for confirmation after submitting it the first time.
The current behavior is bad interface design, because it puts everyone who cannot predict the future in a temporary state of confusion. Not only does it punish responsible users like the OP-- who evidently (and rightly) escaped out and went no further-- but it also rewards risky behavior of the user who is satisfied with an apparent single entry of the password.
If you're concerned about lazy users cutting and pasting, put a warning label advising them not to cut and paste. Regardless: two entry fields in the _same_ dialog, please-- like every other password selection interface I've ever seen in my entire life. There's absolutely no need to avoid standards here.