Okay, here's the news from Facebook:
Friday was the deadline to for departments to put in for who they want. Departments will hand in a list of candidates who they like, and casting is responsible for calling them up, and offering out the positions.
However...
Some people get offered a PI and accept thinking they won't get another opportunity, but later get offered another PI that they want more. And YOU CAN ACTUALLY ACCEPT THE OTHER POSITION!
This means that casting will then have to call the next candidate and find out if they're interested. In some cases, they'll go through an entire stack of people, and have to go back to the department for their next list of picks.
This is the reason why the 31st was the deadline to send in your intern selections, but the 28th of November is when we'll hear something back.
So, yeah, good news for a lot of us.