It actually predates Dybvig's time at Indiana; he started writing it as part of his PhD work at UNC Chapel Hill. Plus, he set up Cadence Research Systems for licensing Chez Scheme, so it was never owned by any university.

The part where Cisco open sourced it is a bit unusual, but it's not uncommon for people to close source and sell systems they create during college or grad school and continue to use them in research.