Wouldn't the above just prevent someone from trying to change their password a second time?
When I get a chance I'll try and fix this correctly. In the meantime, while I won't actually block the form or process, I can at least hide-it. In case it is helpful to someone else...
edit template: lost_password
I kept the title and head alone, but removed the <xf:form> … </xf:form> section and replaced them with css unfriendly (it doesn't matter on the popup for now):
<center>
<br><br>If you have forgotten your password, you can go to the logon page on the main site to request a new password.<br>
<br><br><a href="https://www.x.com/accounts/">https://www.x.com/accounts</a><br><br>
</center>