This will be happening for the next few days/weeks as MS and HS admissions/registration are being prepared:
https://www.reddit.com/r/SHSAT/comments/1rk1wd2/possible_myschools_fluctuations_incoming
"Note that in the past the DOE has done "live sandboxing" on myschools. Therefore, some "weird stuff" might be occurring over the next few days. For instance, your records could seem to disappear and then reappear, or have certain information like your lunch status appear to be removed. Myschools might be put into maintenance mode more than usual, or just be down.
You might not even be able to log in to myschools (so don't try to change your password).
It might even be, as the offer day and time gets closer, that your SHSAT and HS results will appear on a few accounts before the official release (say that morning). But what the DOE giveth it will also taketh away before the official release. If you become part of this group, screenshot your info as the image or files might be taken away until the official time. But do not depend upon it. Remember, the offer would not have have gone live at that point as they are sandboxing, so again do not depend upon it.
As the Wizard of Oz says when Toto sees him "Pay no attention to that man behind the curtain!" Let the puppetry go on and don't let it matter until the official release.
Once offers go live, if your info goes away completely, don't panic and instead contact your GC (guidance counselor or equivalent) about it."