Wow that's strange, seems like their internal server is not updated with the latest TPS stuffs for Nepal. May be somebody punched in June 24, 2015 as the end of registration period in their system. Good thing is that you can resend mentioning the registration time frame may be even with a print out of TPS for Nepal page from USCIS website. But u might wanna wait a while to see if others too get similar notice.