As a new grad from CMU undergrad, every offer I had came with a sign on bonus (n=5). Size ranged from 5k at a smaller public company to 75-100k at a couple of FAANG companies, one of which I was a returning intern at.
Thank you. Those were in cash, RSUs were separate. It is definitely very high, and I feel fortunate to have gotten it. Many of my fellow interns received similar signing bonuses on their return offers, so at least for people in similar situations it's not out of the ordinary.